Running out of fuel @ WOT...85hp Force

[89wrangler]

I have 1988 85hp on a Bayliner 17' Trophy Bass boat. Boat will start fine once you squeeze the primer bulb a couple of time, idle fine, and run great up to a little over 3300 RPM and then will start running out of gas and slow down until it dies if you leave the throttle open. If you back the throttle off, it will idle. Then squeezing the primer bulb I noticed it is not full. Give it a couple of squeezes and will run great up to about the 3300 RPM mark again. I have so far,

checked fuel lines for blockage/leakage
checked to make sure vent was not blocked
change fuel pump diaphragm
new plugs
going to clean carbs this evening.

Any other suggestions on what may be causing this scenario? Thanks!

 

[pnwboat]

Re: Running out of fuel @ WOT...85hp Force

It certainly sounds like a classic case of fuel starvation. Maybe debris floating around in the tank blocking the fuel flow, or pick up in the tank partially blocked. You can test by connecting to a portable tank and see if there's any difference.

 

[89wrangler]

Re: Running out of fuel @ WOT...85hp Force

Thanks for the tip. I will give that a try this weekend with one of my pontoon tanks.

 

[pnwboat]

Re: Running out of fuel @ WOT...85hp Force

One other thing that crossed my mind was the primer bulb itself. The one way valve in them sometimes goes bad restricting fuel flow.

 

[jerryjerry05]

Re: Running out of fuel @ WOT...85hp Force

#2 cylinder runs the pump.
What's the compression?
The gasket behind the pump is it in place?
What condition?
Like pnw said the squeezie can go bad.
Even new right out of the package they can be bad(Tempo).
Ethanol can delaminate the inner section of the hose and it can collapse, replace ALL the lines.

 

[89wrangler]

Re: Running out of fuel @ WOT...85hp Force

Thanks for the extra tips. Picking up some fuel line this evening and a new bulb as I was leaning towards that too. I postponed taking off the carbs until I try these items. The compression is 128psi on number 2 ( other two are 128 and 127) and pump gasket is good. Thanks

 

[Jiggz]

Re: Running out of fuel @ WOT...85hp Force

Or you can install that clear fuel filter between the pump outlet and the carb inlet and that will give you indication where the fuel problem is generally at. If the filter comes up empty (or less than half full) when the engine stalls, it tells you fuel delivery problem upstream of the filter is the source of the problem, i.e. fuel pump, primer bulb, tank vent, pick up, etc. But if the fuel filter is at least 3/4 full then the problem is in the carb system. It is a very cheap mod with the filter costing less than $5 at WM or some auto parts store plus two hose clamps for a total cost of less than $10. And this is a very good and reliable diagnostic tool for now and the future.

I understand there are multiple carbs on this motor, but with two carbs having problems, the engine will stall.

 

[89wrangler]

Re: Running out of fuel @ WOT...85hp Force

Changed out all the old gas line and installed a new primer bulb. Boats now runs great! I am leaning toward it was mainly the Bulb as the new one will get really firm when squeezing where the old one you could feel the fuel in it, but did not seam to fill up. Now just have to get a replacement prop as the wife neglected to put the motor up when loading the boat onto the trailer this past Saturday and re-shaped the one that is on it :facepalm:

 

[pnwboat]

Re: Running out of fuel @ WOT...85hp Force

I think we've all done that one before! Anyways, thanks for letting everyone know the final fix.

 

[Jiggz]

Re: Running out of fuel @ WOT...85hp Force

Did you also break the skeg, which is supposed to protect the prop?

 

[Big Fish Billy]

Re: Running out of fuel @ WOT...85hp Force

Those reshaped props make great yard ornaments...bring back memories every time you see them...and best of all they're free.....plus you can spin yarns to the neighbors about how that 25 foot shark grabbed a hold of it......

 

[89wrangler]

Re: Running out of fuel @ WOT...85hp Force

Did you also break the skeg, which is supposed to protect the prop?

No, did no break the skeg, just nice scrape. Must have been the angle as it scraped two blades and bent and cracked the third one. Before it becomes yard art or a wall hanger I am going to straighten and weld it up for spare. We shall see. New prop will be here tomorrow, so back to lake this weekend if weather cooperates.