Fuel feed

[Jetfixr]

Alright let me put out the facts. Wellcraft 190 CC. Plastic tank below floor line. Johnson 112 SPL fuel hoses from tank to fuel bulb are new, new fuel bulb, inlinve glass filter, new line to engine. Vent line is wide open and clear, able to blow into tank from vent tube and you can hear it pressure the tank and expell air when you stop blowing, feed line has no check valve, it is cut to correct length per instructions, and when you blow from the line into tank it bubbles the fuel. No restrictions, however wide open throttle running, the engine will run for 5-10 mins and then a suel starvation flame out, pump the ball, twice get's hard and relight runs fine, another 10-15 mins wide open running same thing just looses power. I am stumped here short of adding a low pressure 12volt fuel pump im out of ideas.

Jet

 

[64osby]

Sounds like you might need to keep going down stream.

Possible weak fuel pump. Can you keep it running by pumping the bulb?

Possible sticking float needle. When is the last time the carb was cleaned?

 

[Chris1956]

Does fuel primer bulb collapse? If so, trouble is upstream of it. If not, trouble is downstream of it.

 

[Jetfixr]

I opened the carbs and they were spotless, like they were just cleaned the float measurements i even checked them and they were good, the needles were done back in march along with the carbs initial cleaning. I may just change out the pump just for the heck of it. Yes the primer bulbe went flat on me the first time.
Thanks guys for the remarks.
Jet

 

[Chris1956]

If the primer bulb went flat, the fuel tank vent or "plumbing" between the primer and the fuel tank are obstructed or partially obstructed. Loosen the fuel tank cap and see if it happens again. If the primer bulb stays full with the fuel tank cap open, the fuel tank vent has some restriction.

They can be partially clogged, where running full speed for a few minutes is necessary to collapse the primer bulb, and running at slower speed works fine....

 

[emdsapmgr]

Once the engine runs and starts to draw fuel through the hose, the hose bulb will soften-but should not collapse. That's normal. It is possible the old-style fuel pump may be weak. If so, the pump may not be able keep up with the fuel consumption of the carbs at WOT and the bowls will drain of fuel, possibly shutting down the engine. To test for this, have a buddy constantly prime the fuel hose bulb when at WOT. If the engine runs just fine as long as you constantly prime the fuel hose bulb, the pump may be weak and in need of replacement. Also possible it's an ignition problem. Weak ignition components tend to fail once the engine heats up to normal operating temps. So, next time you have a flame out, check for spark on the plugwires. An inductive timing light is helpful for this test.

 

[Jetfixr]

Going to replace the thru hull vent fitting and sea trial tomorrow. Keep you posted.

Jet

 

[F_R]

Why not cut to the chase and temporarily install a fuel pressure test gage? They don't cost much and will save a ton of $$ in un-necessary parts replacements. Your original post strongly suggests a bad fuel pump, but the gage will confirm that if it is the case.

 

[Jetfixr]

What pressure should i see in the fuel line to engine? I have a gage i can install. If the pump is sucking down the bulb then i would agreee it could be questionable.

 

[racerone]

The bulb does not need to stay hard once the motor is running.----If bulb gets sucked flat there is no problem with the fuel pump.--Ckeck the pick-up tube in your fuel tank.-----What are the compression values on this motor ?

 

[emdsapmgr]

The hose bulb can also get sucked flat if one of the internal ball valves is not functioning properly.

 

[F_R]

What am I missing? Where was it said that the primer bulb was being sucked flat????
Anyhow, do we know what the model number is? Typical pressure at full throttle is about 3psi, but would have to verify that.

 

[Jetfixr]

1996 112sledr the compressions are all above 110, the thru hull ffitting is wide open next is to see what fuel pressure is, there is no check valve in the fuel feed, the fuel pickup is the correct length. I am stumped...Thanks for the responses and ideas!
Jet

 

[emdsapmgr]

What happened when you had someone constantly prime the fuel hose bulb?