Merc 2 Stroke Power Fuel Delivery Fluctuation Issues

[baby1]

I could be  wrong/// but my redneck ways  have worked before//

[CTsalt12]

Thanks all. 

CLM-Interesting about wood sinking, didn't know this.

Fitz-makes sense that if bulb is deflated the pump has to be working because it's clearly sucking fuel to deflate the bulb.

I guess the wood piece may be clogging up the pickup, it's just surprising because there's so little space between the pickup and the bottom of the tank I'm not sure the piece would even fit in there.  And the dowel is round so it couldn't cover the whole surface area of the pickup.  Gotta get that thing out.  Also have to check the fuel vent, I've had issues with those screens getting clogged up before. 

[fitz73222]

This must have been the weekend for flat primer bulbs! This is the god's honest truth.... I got a text on Saturday from a member on ABC asking what does it mean when my primer bulb goes flat and the engine won't run. This is a 250 Opti. ( I had know idea he was dead in the water) I texted back that it was 1) Tank not venting right or 2) water separater plugged from contaminated fuel, loosen or remove the fuel fill cap and see if you can reprime the engine and it should run (allowing air to enter the tank) Never heard from him until today. While doing the things I asked him to try, his cell phone takes a swim in the ICW, no more texts! So he took off his fuel fill cap and the engine ran perfect the rest of the day. Now he has to figure out the vent issue but at least he had a good day and got home with the family safe and sound. Can't make this stuff up...

[CLM65]

The dowel blocking the pickup may be a stretch, but generally speaking, any loose debris in the tank has the potential to cause problems.  Maybe you will find some other stuff in there too.  I also like Fitz's suggestion of opening the fill cap to rule out or confirm a vent issue.  Simple and effective.

[CTsalt12]

Re opening this thread to address my never ending fuel issue saga.  I've replaced the fuel pickup, anti siphon, fuel lines under deck and above deck, and primer bulb.  In line fuel filter as well.  Gas is clean.  Tried opening vent.  Thought I had the issue figured out, then when the boat was under load yesterday with a full boat it bogged down while up on plane numerous times.  Earlier that morning fishing with me and one other it ran fine on plane.

As far as I'm concerned the only pieces left in the fuel statem to check are fuel water separator and the actual water separator head unit that the canister screws into.  Do these go bad?  There's also a very short line from separator to the hull.  Really running out of options here and considering the pump could be bad.  Replacing rest of fuel system today and will test and see.  Any other ideas?

[fitz73222]

You have a 4 cylinder 115 Merc, correct? Did you replace the fuel filter inside the engine and did you run the engine on a remote 6 gallon tank with a different fuel line and primer bulb and the problem still exists?

[CTsalt12]

Fitz, yes yes and yes.  I did not run on a different primer bulb but replaced it.  Never had issues with remote tank but my issues are inconsistent anyway, although become much more consistent the last month.

I may have found the culprit though.  When I replaced the fuel line from tank to engine I for some reason overlooked the 2nd line from separator to fiberglass before primer bulb line starts above deck.  About a 2 ft stretch of hose that was also delaminated and probably causing blockage.  I also emptied fuel water  separator and the gas was filthy.  Weird it was fine a month and a half ago.  I poured the gas in a solo cup and in 10 minutes it melted through the cup onto my dock.  Anyone know why this happened?  Also Replaced fuel separator bowl and head unit it screws into.  It was very corroded. 

Ran it all around the sound today fishing, good fuel flow all day.  True test will be when boat is loaded up with people.  Replaced all fuel components at this point, about $200 later.  All hoses and attachments were at least 4+ years old. 

[fitz73222]

Gas and solo cups don't mix, try styrofoam cups, they melt in about 2 minutes. Glad you found the problem.

[CTsalt12]

Update:

After all fuel lines and components are replaced, it's running a lot better.  Problems with engine bogging down are fixed, all is well. 

However, there is still a small issue bugging me.  I've noticed a power fluctuation.  I was cruising along at 3500 RPMs and 24 mph steady, and the boat picks up to about 4000 RPMs and 27-28 mph, without me touching the throttle.  I notice slight power fluctuation from time to time, not usually as dramatic as this.

I also notice that unfortunately, the boat does not have the juice that it used to.  At 4000 RPMs I used to be closer to 33 mph.  I

 suspect the carbs could be the issue.  I haven't had them rebuilt or cleaned since the beginning of the season in 2013.  But my gas also is clean, I do a sample from time to time, no water.  Could the fuel pump be the issue?