# Prime...what am I missing?



## WhyMe (Apr 21, 2013)

After getting towed in on Saturday. I got new filters. Stop, Back up...Ok. At sea the engine was starving for fuel then shut off. Over and over. Today on land I got two new filters filled both with fuel and then put them back on.
The engine is a 1998 Mercury 225 EFI Offshore. The problem is repeating itself with new filters. I have also noticed that the primer bulb will not prime nor stay primed when the engine is running for a minute or up to 30 second. The engine will only stay running when the filter under cowling is primed by hand. The primer bulb appears to be in good shape, but looks can be misleading. Any ideas?
What am I missing. Thanks

WhyMe 
Mako My Dayo


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## lastcast (Oct 12, 2007)

I would use an external tank to help find the problem area. By "the bulb not staying primed", are you saying it's getting sucked flat? Collapsed fuel lines from ethanol maybe.


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## Sequoiha (Sep 28, 2007)

If you can't pump the primer bulb and get fuel, could have a cracked pick up tube in the tank, see it all the time, split fuel line or a hole in the line some where, if it sucking flat probably the anti siphon valve, as suggested earlier try another tank.


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## WhyMe (Apr 21, 2013)

When the engine is running the bulb will not go flat. It retains its same shape. The engine shuts down after it uses all the fuel in the filter under the cowling.
WhyMe 
Mako My Dayo


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## lastcast (Oct 12, 2007)

http://www.thehulltruth.com/boating-forum/280073-mercury-efi-fuel-pump.html#b


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## pappastratos (Oct 9, 2007)

we had the exact problem, after fuel lines, bulb, plugs, filters, pump,,,it was a big hunk of silicone stuck in the fuel tank pick-up tube. Pulled it out, then it ran like new,,,,Try the portable tank route, even if it is the lawn mower gas can, make sure its clean, no filter, new fuel line. Stick line in the tank, to the primer bulb, then to the motor.


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## WhyMe (Apr 21, 2013)

I can't even get the bulb primed at all. I took the line of where the fuel goes into the fuel pump and then tried to prime the bulb as well as looking to see how much fuel is coming out. To me..not a lot of fuel, but some fuel.
WhyMe 
Mako My Dayo


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## floater1 (Oct 31, 2007)

Sounds like the inner primer bulb is split or has a pinhole

Sent from my SAMSUNG-SGH-I537 using Forum Runner


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## lastcast (Oct 12, 2007)

Blocked pick up or fuel line. As said, pull your fuel line off of the input to your ext primer bulb, put a piece of fuel line on it and stick it in a tank. Sounds like you have a blockage or collapsed fuel line.


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## WhyMe (Apr 21, 2013)

Ok...what I think I'll do s take each section of hose and shoot air through it ,to make sure and clear any blockage. 
WhyMe 
Mako My Dayo


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## Deeplines (Sep 28, 2007)

Like stated, try a external tank. Sounds to me like also posted, its your pick up in your fuel tank.


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## WhyMe (Apr 21, 2013)

Deep lines....I will try the external tank first before the compressed air. Question...should I run the external tank line before or after the first filter (water fuel filter..the big filter..)?
WhyMe 
Mako My Dayo


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## lastcast (Oct 12, 2007)

I would try it right before the primer bulb first. Basically your using it to find out where the problem is, then you can start eliminating or adding. But if it's good right before the primer bulb then it's just fuel line and your pick up/screen (I think). And if you use air to clear your pick up your just going to blow it back in the tank "for later".


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## fairpoint (May 9, 2013)

Have you checked the vent for the tank..? I have had vapor lock and couldn't get any fuel....Sometimes the screen corrodes or dirt daubers nest in it.....good luck


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## WhyMe (Apr 21, 2013)

Well this is what I did. I undid the hose on the back side of the primer bulb. Put that in the external tank then primed the bulb started the engine. It ran just fine. I noticed that the end of the primer bulb it was connected to a extra fuel pump. What... I disconnected the fuel line from the water fuel filter to the extra pump. I then reconnected the main primer bulb fuel hose to the out part of the water fuel filter. The primer bulb primed ( not real tight , but one could tell you getting fuel in the bulb) and the engine started right up. I will try again tomorrow to see if its still working. I will post the outcome.
Thanks
WhyMe 
Mako My Dayo


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## lastcast (Oct 12, 2007)

Don't have a clue on the "extra fuel pump" but it sounds like your getting somewhere. Good Luck and post it.


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## WhyMe (Apr 21, 2013)

I never seen one like this before. I will try to take a pix of it and post it tomorrow. I will say that when ever I tried to prime the primer bulb it has ever gotten very hard or stiff (That crap sounded so bad) , but you no what I mean.
WhyMe 
Mako My Dayo


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## Chapman5011 (Mar 7, 2013)

WhyMe said:


> After getting towed in on Saturday. I got new filters. Stop, Back up...Ok. At sea the engine was starving for fuel then shut off. Over and over. Today on land I got two new filters filled both with fuel and then put them back on.
> The engine is a 1998 Mercury 225 EFI Offshore. The problem is repeating itself with new filters. I have also noticed that the primer bulb will not prime nor stay primed when the engine is running for a minute or up to 30 second. The engine will only stay running when the filter under cowling is primed by hand. The primer bulb appears to be in good shape, but looks can be misleading. Any ideas?
> What am I missing. Thanks
> 
> ...


Not sure if I said earlier or not but take your primer bubble off and shake it. When I had the same problem, I could hear things rattling inside my pump bubble. It was the same orange stuff that was packed in my filters. I'm told it's ethanol . But that seems to be the small engine story now days.


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## Deeplines (Sep 28, 2007)

Mike, One of my bulbs doesn't get hard either. (Yea, it sounds bad.) Like Lastcast posted, if you blow your line out with air all that my happen is next time you are 25 miles offshore it picks it up again. 

Interested in seeing the picture you post about the extra fuel pump.


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## WhyMe (Apr 21, 2013)

Ok... I'm out right now, but I did start the engine up this morning. The bulb did not prime hard, but the engine started and then soon ran out of fuel. I'm now at the main water fuel filter. All lines are disconnected, but I had to go. I will be taking the filter housing off and checking that out next. If that Fails , its the main fuel line back to the tank.
Whyme
Mako my Dayo


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## WhyMe (Apr 21, 2013)

Ok. I took off the main housing filter bracket and made sure no blockage and then remounted the filter bracket on the outside of the boat. See pix. I blew into the main hose back into the fuel and I felt nothing blocking the hose.

I then primed the big filter and started the engine. It ran great up until all the fuel ran out of the filters and hose. I was still unable to get the bulb hard, but when I put the fuel line in a external tank the bulb primes right up. Help...I will say the my fuel gauge is not work, but I put in 40 gallons of non-ethanol fuel. I started at Daybreak and went to the ECUA Culverts before my mishap. Also here is that extra fuel pump. I think?
WhyMe 
Mako My Dayo


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## WhyMe (Apr 21, 2013)

Another pix.
WhyMe 
Mako My Dayo


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## kanaka (Oct 3, 2007)

If you have a fuel pump, and you have 2 of em, why do you need a primer bulb? I'd bypass em both and see what happens.


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## Deeplines (Sep 28, 2007)

With what you posted last I would double check my line from filter to tank for area letting air in.


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## Sequoiha (Sep 28, 2007)

Did you ever check for a cracked pick up tube like I previously posted?


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## Florida-Lis (Mar 5, 2014)

I just want to make sure I'm hearing this right. Your using an external tank through the fuel water separator / then goes to fuel line to primer bulb / then fuel line to motor.

It still didn't run continuously?

Bypass the filter.


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## WhyMe (Apr 21, 2013)

Florida.. No. Primer bulb..hose into tank. Primes right up and engine runs just fine.
I might not have time today to look at it, but I'm getting ideas on whats wrong. I also by passed the external fuel pump.
WhyMe 
Mako My Dayo


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## The Maintenance Shoppe (Nov 5, 2007)

Hey the piece that you think is a fuel pump is NOT a fuel pump, it is a flow sensor for flo scan fuel meter. If you don't have the floscan gage then remove the sensor, it can cause a flow restriction.
Before you get back on the water you need to move the primer bulb to before your fuel filter.


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## WhyMe (Apr 21, 2013)

Flow sensor tells you GPH? Right. I have a gauge on the dash, but only reads 0. Thank you on that piece of info.
WhyMe 
Mako My Dayo


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## The Maintenance Shoppe (Nov 5, 2007)

yes you are correct, if it doesn't work, then remove the sensor. If the internals of the sensor are siezed then it will be a fuel restriction.


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## WhyMe (Apr 21, 2013)

Well, after messing around with today and I tighten all fittings up. That also includes in the one under the coffin lid. I checked the air vent as well. That was ok. I also bypassed the flow sensor. Now the primer bulb primes up and engine starts and stays running. I want to say thank you the members that put their two cents in on helping me out.
I hope this does it.
WhyMe 
Mako My Dayo


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## Deeplines (Sep 28, 2007)

So the Fuel Flow sensor was the culprit? 

Glad you posted all, this is a great trouble shooting thread.


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## lastcast (Oct 12, 2007)

Thanks for the follow up. Glad you found the problem.


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