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Author Topic:   2001 Mercury 90 Not Getting Fuel
jtms posted 11-14-2009 12:54 PM ET (US)   Profile for jtms   Send Email to jtms  
[I] took my Montauk out for a cruise yesterday and the [2001 Mercury 90-HP] engine sputtered then went out on me. I took off the fuel-water separator and emptied it out. There was some water, but not that much. Now, I cannot get the engine to start. Seems that there is some filter somewhere that is clogged and preventing fuel from getting to the engine. Any suggestion as to where any other filters could be that are clogged? The fuel-water separator is brand new. I ran it last weekend and the boat ran perfectly--strange.

Thanks for any tips-Jason

Newtauk1 posted 11-14-2009 01:05 PM ET (US)     Profile for Newtauk1    
Is the primer bulb firm? I would try running a separate fuel tank with fresh fuel.
Newtauk1 posted 11-14-2009 01:14 PM ET (US)     Profile for Newtauk1    
Did you replace the fuel filter and fill new one with fresh fuel?
jtms posted 11-14-2009 01:21 PM ET (US)     Profile for jtms  Send Email to jtms     
Primer bulb is firm. Fuel is two weeks old and I always put [Stabil] in it. I kept pumping the bulb until is was full. Wouldn't this also fill the fuel-water separator with fuel?
RevengeFamily posted 11-14-2009 01:21 PM ET (US)     Profile for RevengeFamily  Send Email to RevengeFamily     
Jason--What type of engine? Year? A serial # would be very helpful as well.


jtms posted 11-14-2009 01:35 PM ET (US)     Profile for jtms  Send Email to jtms     
It is a 2001 Mercury 90 Saltwater, serial number is 0T276950. Thanks for the tips!
Newtauk1 posted 11-14-2009 01:56 PM ET (US)     Profile for Newtauk1    
Fresh fuel , new filter and water in the filter? Something does not seem right. Where did the water come from? Check all fuel fittings and lines. A pin hole could cause fuel starvation. How old are the fuel lines?
jimh posted 11-14-2009 06:19 PM ET (US)     Profile for jimh  Send Email to jimh     
It should be possible to follow the fuel flow path by just making a close visual observation of the engine. If there is a filter in the path it should be visually apparent. I don't think there is any sort of hidden fuel filter.

Is this engine a two-cycle engine? Does it have carburetors?

jtms posted 11-14-2009 06:53 PM ET (US)     Profile for jtms  Send Email to jtms     
It is a 2 cycle, so it must have carbs correct? I am sure the water came from ethanol. Ethanol "makes water" as they say. I have the 10 micron filter so it did its job. I just went on the boat again and I think the bulb or something is clogged. When I prime the bulb I can't even get gas to enter the fuel/water separator. The bulb has to be bad. If that isn't bad, then it must be the fuel line from the tank to the filter....I think :). Any other suggestions. I just figured I could trouble shoot before calling a mechanic to come out and change a $10 line.

To answer another question, I am not sure how old the fuel lines are. I just got that boat and I can assume that they are the same age as the boat; 8 years. The boat only has 175 hrs. and the lines look to be in good shape.

Thanks for any tips.

RevengeFamily posted 11-14-2009 07:33 PM ET (US)     Profile for RevengeFamily  Send Email to RevengeFamily     
According to Jason's serial number this is a carbed/oil injected engine.

There should be a small fuel filter just below the fuel pump. It's a in line filter. A cream colored plastic. It's part number is 816296Q-2, About $6.00. There is an easy test for this small filter.

On the side of the carb bowl is a small drain screw. Crack the screw loose and see if fuel leaks out. With the screw loose, squeeze the primer bulb and see if fuel leaks out rapidly. If you get a good flow of fuel I would not suspect your filters or lack of fuel.

Keep us posted,


RevengeFamily posted 11-14-2009 07:44 PM ET (US)     Profile for RevengeFamily  Send Email to RevengeFamily     

If the fuel line before the primer bulb is plugged, after squeezing the primer bulb it will stay flat do to lack of fuel flow.


Anjin posted 11-14-2009 09:04 PM ET (US)     Profile for Anjin  Send Email to Anjin     
I had a similar problem with the same engine except mine is a 2005.

Emptying out the filter once wasn't enough. I had to do that a couple of times. I also took the nozzle off the end of the hose and pumped maybe a quart of "fuel" through it by squeezing the primer bulb. Mine ran normally after that.

I hate this ethanol fuel.

bloller posted 11-14-2009 09:29 PM ET (US)     Profile for bloller  Send Email to bloller     
Take the fuel connection off the motor and push the valve in on the fitting while pumping the primer bulb until you get fuel. Reconnect to engine and you are ready to go.

I don't know why but whenever I change or inspect my spin on fuel filter I have to go through this process for fuel to get to my engine.

jtms posted 11-14-2009 10:00 PM ET (US)     Profile for jtms  Send Email to jtms     
Wow, you guys are great! Thanks for all of the tips. I will try doing everything tomorrow and I will report again. Thanks again.

On a positive note, I love the simplicity of this boat. On my last rig, I can only imagine how much of a pain this would have been to do.


Newtauk1 posted 11-15-2009 02:29 AM ET (US)     Profile for Newtauk1    
Do not forget to fill the fuel filter with fuel:) before attaching.
newt posted 11-15-2009 10:40 AM ET (US)     Profile for newt  Send Email to newt     
I'll second the above recommendations to either fill the filter with fuel prior to screwing it back on, or disconnect the fuel line at the engine and squeeze the bulb until you have fuel coming out. Sometimes if you have fuel in the lines downstream of the filter, the Carb floats won't allow any more flow even though the filter is empty.

Once you get fuel flowing at the engine, you might as well siphon a few gallons into a spare container. Then, check the filter. If there is still water in the filter, then you should keep siphoning off gas until the water is gone. You can dump the siphoned gas back into the boat, since the water should have been removed by the filter.

jimh posted 11-15-2009 11:24 AM ET (US)     Profile for jimh  Send Email to jimh     
Reading my reference article

A Primer on Primers

will help you understand how to use the primer bulb as a diagnostic tool in evaluating problems with fuel delivery.

jtms posted 11-15-2009 12:31 PM ET (US)     Profile for jtms  Send Email to jtms     
I just did all of the recommendations and it still will not start. I checked the filter and even disconnected it at the proximal end and squeezed the ball valve and fuel went through fine. So, I checked everything that could clog it from the gas tank to just past the inline fuel filter in the engine. I even pumped out a 1/2 gallon of fuel into a bucket. When you squeeze the ball it feels like something is still clogged. I don't know what else could be clogged. Could I have a bad fuel pump? I would think that pumping the ball you could get enough gas manually to at least get it started??? Is there anyway that some valve in the carbs is not allowing gas in?

I even sprayed some engine start spray in the air intake and got her running momentarily then it would cut off b/c of lack of fuel. Any other suggestions?


bloller posted 11-15-2009 01:33 PM ET (US)     Profile for bloller  Send Email to bloller     
Make sure you are not letting air into the fuel system somewhere. I once had a fuel connector at the fuel tank not seal properly allowing air into system. Engine would not start.

jtms posted 11-15-2009 02:38 PM ET (US)     Profile for jtms  Send Email to jtms     
I will check to make sure seals are tight. What is the deal with the flush hose on the Mercury? Looks like you have to buy some type of attachment to get the hose to screw in? Seems counter-intuitive? Why wouldn't they just put on on the flush hose? Anyone know where I can get one? I have ear muffs, but sometimes I don't feel like hooking those up and it would be nice to just plug the hose into the flush hose and let er' rip...
L H G posted 11-15-2009 03:03 PM ET (US)     Profile for L H G    
I have two new 90's, and the factory installed flush hose comes complete - just attach the hose. It's a very nice flushing detail. If you are missing some components, go to a Merc dealer for parts.
jtms posted 11-15-2009 04:42 PM ET (US)     Profile for jtms  Send Email to jtms     
This might be more than I can handle. Just got the boat cranked, but it was weird b/c it would only crank when I had the engine tilted up with the ear muffs on??? When it was running, it was leaking oil through the cowling pretty good. Might have to call a mechanic on this one. I don't have any idea what is going on. Anyone ever had this happen before? I couldn't get it to crank when the engine was down in the water....strange. Maybe the oil injection hose is loose????
jtms posted 11-15-2009 04:55 PM ET (US)     Profile for jtms  Send Email to jtms     
just did a search and sounds like the oil tank leaking is a common problem. It has been leaking slowly when the engine is tilted for a while. I guess this was accelerated b/c it was running while tilted. I will get a new cap. What a crap design!!! Still doesn't explain why the engine will run while titled with ear muffs and it won't run when in the down position??? Thanks for any tips-
Anjin posted 11-16-2009 01:29 AM ET (US)     Profile for Anjin  Send Email to Anjin     
There is a little cap on top of the oil reservoir (not the fill cap) with a small valve. If that is missing it will leak oil when tilted up.

Do you have a service manual? At this point it seems like you've exhausted all the easy fixes. You have to do some trouble shooting and without a service manual you are shooting in the dark. Even with one ...

Is your main fuel line old cheap non-ethanol resistant fuel line? If so the inside could be decomposing and clogging up your fuel system. (If your fuel line doesn't have a red stripe down it's entire length it is not the right type of fuel hose.) If it got into the carbs, you probably have to rebuild them. Otherwise are you going to trust that motor out on the ocean or where ever you take it? I replaced mine with Trident barrier lined fuel hose. expensive but good.

Replace the inline filter under the cowling maybe there is debris inside that clogs the line when tilted down and moves back to unclog when tilted up.

Same with carburetors maybe tilting the motor moves something that is clogging something up inside the carbs.

I don't know where you live but in so Fla all these guys that hold themselves out as "outboard mechanics" are a bunch of "wham bam thank you ma'am" money grubbing hacks. Often you are better off buying a service manual, tools you don't have but need for the job , and new parts rather than going to one of these butchers. but maybe you know a good honest competent one .... outboard mechanic that is, not butcher.

jtms posted 11-16-2009 02:12 PM ET (US)     Profile for jtms  Send Email to jtms     
How tough is it to replace the main fuel line? Doesn't look that tough. Is there something I need to watch for? Anytime I hear "fuel lines" it gets my attention. Something I can easily do myself or do I need to get a pro to install them. I am not the most handy person, but I am getting better.

newt posted 11-16-2009 03:55 PM ET (US)     Profile for newt  Send Email to newt     
It really isn't hard to replace fuel lines, but before you do it, try running the engine with a small portable tank hooked directly to the engine, as this will eliminate a problem with your existing tank, existing fuel lines, external filter, etc. Also, change the fuel filter under the cowling In fact, you could just purchase a fuel line with primer bulb, connect one end to your engine and drop the other end into any old gas can that you already own. For $20 you can eliminate a lot of guesswork.

However, the fact that your engine runs when tilted up but not while tilted down, seems to indicated that the problem is not anywhere in the fuel supply.

Did you try opening the carb drains as suggested by [RevengeFamily]?

If you have fuel in the carb bowls, then the engine should run until it uses up the fuel in the bowl.

If you don't have fuel in the bowl, yet you do get fuel to the under cowl filter, then it sounds like the floats are stuck shut and you need to pull the carbs and clean them.

Also, make sure that there is not a fuel line getting pinched somehow in the down position, but not when tilted up.

jtms posted 11-16-2009 04:58 PM ET (US)     Profile for jtms  Send Email to jtms     

I pretty much eliminated the "running when tilted theory" today. I got the engine to run when it was in the down position. I think it was just pot luck that it happened to run when tilted yesterday. There is something clogged or pinched that allows fuel to pass sometimes and other times it does not. Sometimes I can pump the bulb and I can hear and feel fuel moving. After I do this, I can get the engine to run until the engine runs out of fuel. I had the engine running for almost 20 minutes today and it sounded fine (until it ran out of gas). I even put it in gear at the dock for 10 minutes or so. Other times, I try and squeeze the bulb and it is hard and feels like it is clogged at the other end, but I am not sure what end is clogged yet.

I did crack the drain bowl and some fuel came out. It would not come out as I was pumping which makes sense b/c it doesn't always allow fuel to be pumped for some reason.

I am going to definitely change the in-line filter this week. The BW dealer also said that it could be a clogged diaphragm. Never heard of this, but he said it could be clogged as well. I am going to change that also b/c it is $20.

Do you think that hooking up a gas tank is still a good idea? I am pretty confident that the engine is running fine as long as it can get gas. I am confident that the engine will run find with a separate tank b/c it runs fine when I am able to get the bulb to pump now.

Don't tell me this is as simple as a bad bulb??? Just thought about that. Would explain a lot.

As always, thanks a bunch for the tips!!!! This is a great site!

newt posted 11-16-2009 07:25 PM ET (US)     Profile for newt  Send Email to newt     
You should definitely run the engine off of an auxiliary tank since you can easily eliminate everything in the fuel supply chain up to the engine. If your motor runs fine on the auxiliary tank, then you know for sure your problem is either the fuel line, primer bulb, filter, or tank. If your motor doesn't still doesn't run well, then you have narrowed it down to the engine side.

Try an auxiliary tank. If the motor runs fine AND you have good fuel flow to the under cowl filter, then it sounds like a sticking float/needle valve assembly.

jimh posted 11-17-2009 09:03 AM ET (US)     Profile for jimh  Send Email to jimh     
The only reasonable inference that could be made regarding the engine running only when in the tilted position is perhaps that there is a problem with the carburetor float valves, and, due to orientation when the engine is tilted, the problem is temporarily relieved. Other than that, I cannot see any basis for the engine not running in its normal operating position.

If the fuel primer bulb is working properly, and if the engine fuel pump is working properly, yet there is not fuel provided to the engine, it would be reasonable to suspect that the float valves in the carburetors were not working properly, that is, they might be stuck in a closed position.

Newtauk1 posted 11-17-2009 09:45 AM ET (US)     Profile for Newtauk1    
Is it a Tempo primer bulb? Either way I would consider changing it. If that is not the problem you have a spare for the future as they do fail.
JonGold posted 11-18-2009 07:35 PM ET (US)     Profile for JonGold  Send Email to JonGold     
Maybe I missed it in an earlier part of this post, but have you made sure the vent on the fuel tank cap isn't getting blocked and creating a vacuum. I took my Montauk out last Friday, it ran for about 20 minutes and died. As soon as I cracked the fuel fill, it started and ran fine for the entire day.
jtms posted 11-19-2009 11:20 AM ET (US)     Profile for jtms  Send Email to jtms     
It appears as if the engine is fixed. I ended up changing the bulb and grey hose and this didn't do the trick; same problem. I then changed the $7 in-line filter and the engine immediately cranked up and appears to be running fine. I haven't had a chance to sea trial her so I still have my fingers crossed, but I let the engine run for 45 minutes at the dock and all appears to be fine.

Interesting that the in-line filter worked fine when I tested it disconnected while pumping the bulb. I guess as someone mentioned it might have some particulate in there that sometimes clogs and other times didn't.

Regardless, I have a new fuel hose that will hopefully preemptively solve any future issues and all appears to be fine. Thanks to all for the tips. I definitely learned a lot about the engine and if this problem comes up again I will definitely know how to troubleshoot more effectively.

Newtauk1 posted 11-19-2009 12:22 PM ET (US)     Profile for Newtauk1    
newt posted 11-19-2009 12:59 PM ET (US)     Profile for newt  Send Email to newt     
Good to hear you figured it out. I misread your prior posts and thought you changed the filter to begin with. You probably want to change that filter every year as part of your maintainance routine. It is $7 well spent.
Newtauk1 posted 11-19-2009 04:25 PM ET (US)     Profile for Newtauk1    
Did you use zip ties to secure the hoses or something else?
jtms posted 11-19-2009 08:20 PM ET (US)     Profile for jtms  Send Email to jtms     
Yes, I did use zip ties. Thanks for the tips. Everyone on this website is really helpful!
jtms posted 11-21-2009 06:14 PM ET (US)     Profile for jtms  Send Email to jtms     
Well the saga continues :) Ran it today and it went out on me again. Definitely sounds like the carps are gummed up. It was kind of "sputtering" the whole time. I hooked up a separate tank with fresh fuel and I couldn't even get it started. Unless anyone has any other suggestions, I think I have pretty much isolated it to the engine. It has to be the carbs or maybe some of the hoses are corroded in engine but I doubt that's the case.

I also cracked the fuel as someone else mentioned and this didn't do anything unfortunately.

Since it is only 3 cylinders hopefully it won't cost too much to get them cleaned out.

Anjin posted 11-22-2009 09:08 PM ET (US)     Profile for Anjin  Send Email to Anjin     

My theory: the fuel lines

Parts of the inside of them are corroded sending small bits of debris into all parts of your fuel delivery system. Try cutting open the in line filter you removed from the engine and see if there's anything in it.

At this point do everything else that hasn't been done:

1. Replace all fuel lines, i.e., fuel lines from tank to filter; from filter to motor; and all the fuel lines under the cowling to fuel pump and from pump to all the carbs; and replace the in line filter you just replaced too

2. Rebuild all the carbs (you need compressed air to do it right)

3. replace the fuel pump or rebuild it.

4. replace the fuel/water separator filter.

I think this basically constitutes a complete rebuild of the entire fuel delivery systems. If you don't replace the fuel lines you could re-contaminate your freshly rebuilt carbs and fuel pump and waste all that work.

jtms posted 11-23-2009 02:02 PM ET (US)     Profile for jtms  Send Email to jtms     
Wow, this is a lot of work I have to do. I will take a look at the lines in the engine again, but they appeared to be in good shape before. I spoke to the mechanic at the local BW outfit, and he believes it is the carbs. I am not sure how much the people that owned the boat before me actually used it. He said he sees it all the time and it doesn't take long for the carbs to gum up. In my case, he believes they were gummed up before and my using it prob. loosened some sediment up and that explains why it works sometimes.

In an ideal world I will do everything you mention, but I don't really know how to do all of that. Off to the mechanic I go. I am going to have them take a look at the carbs and the hoses inside the motor for starters. If it is the fuel lines, I can change those out myself. I can't imagine sediment getting through a Racor filter and also an inline filter to the carbs. Whatever caused it, is definitely in the carbs now. If not, then it would have run fine with a separate tank (which it didn't)...correct???

Thanks for all of the tips. Only had the boat since end of August and this is really ticking me off. I am sure this is caused by the folks before me not taking proper care of the boat....ARGHHHH!

Anjin posted 11-23-2009 08:42 PM ET (US)     Profile for Anjin  Send Email to Anjin     

You can just replace the inline filter again. If it runs fine for awhile then develops the same problems again then something is continuing to clog that filter. If your fuel tank is clean, and the fuel water separator is clean, then where else can it come from?

Usually carbs gum up when fuel mixed with oil sits long enough in the carbs for the fuel to dry up leaving the gummy oil residue. That is what causes the problems.

meangene33 posted 08-15-2010 03:17 PM ET (US)     Profile for meangene33  Send Email to meangene33     
I have had all of the same problems, you are having. I put a new in line filter,and I cut the old one, in half, and and their was a segment split letting small particals through.I cleaned the four carbs.And to my suprise they were not dirty. Put all back to geather and still would not run wright. Then I bought a Clymer book on the 90 hp four stroke.And started reading about the carbs.I am 75 years old,and when they say inline filter,I would not have thought to look in the fuel line at the carbs.There is a 1/4 inch dia. filter in the fuel line at the carb.and they were about half pluged. Clean them up and running great. Hope this helps,

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