force dying out on high throttle as time goes on oil mix? octane?

[compute42]

I bought a used boat with a force 125... ran fine the quick runs I gave it before and just after I bought it. Had a mechanic come out, give it a once over etc... Sprayed tons of carb cleaner... etc.. didn't adjust any of the mixture stuff.

Previous owner is unreachable, and I can't find out what fuel mixture/setup he was using.
So I used up the fuel in the tanks from the previous owner, ran fine... I went and got fuel 87 octane, mixed 40:1 (per mechanic recommendation) its E10 ethanol, didn't add any stabilizer or anything....

Boat runs crappy now, full throttle works for about 10-15 seconds then starts to die, if I don't throttle back engine will die out... runs fine at low speed, but after 15-20 min runs rougher.
Now that being said I just am thinking now I didn't have the fuel vent open as far as I could???

Wondering what ya'll are running for fuel/oil, octane? stabilizers? This is driving me nuts, seems to not be running as well on the new gas... Maybe I'm just a dummy and didn't have the vent open far enough, I'll try that tomorrow.

TIA

 

[pnwboat]

Re: force dying out on high throttle as time goes on oil mix? octane?

50:1 is the recommended ratio. 40:1 is OK, but I would go to 50:1 next tank. If the gas tank is not vented properly, it will definitely affect the ability of the fuel pump to pump gas. Open it up all the way.

 

[compute42]

Re: force dying out on high throttle as time goes on oil mix? octane?

Ok vent didn't do the trick... would 40:1 and 87 octane really effect performace this much? I guess I'll fill the 1/2 tank with 60:1 and some high grade gas and see what That does.

 

[compute42]

Re: force dying out on high throttle as time goes on oil mix? octane?

OK no luck with the 92 octane and less oil... seriously why would using carb cleaner on the engine cause it to run so crappy at high throttle.
Fuel issues obviosuly.. I guess I'll check the filter and lines etc... But nothing should have changed. Any ideas of where to look would be great. Boat is in the water, no trailer, basic tools.

Thanks

 

[trendsetter240]

Re: force dying out on high throttle as time goes on oil mix? octane?

The ethanol in the gas might have loosened up some gunk and clogged up the fuel system. You should pull the carbs and overhaul them. It's not enough to just spray the carb cleaner into the carb throat. This does nothing for the fuel inlet to the float bowl or the jets.

50:1 is the correct fuel mixture but 40:1 should not cause the issues you describe.

 

[compute42]

Re: force dying out on high throttle as time goes on oil mix? octane?

umm, isn't there something else I could try before a total rebuild of the carbs? I'm 99% the previous owner ran E10 fuel anyhow as well, and had those in the tanks when I ran it.
Fuel filter cleanout/replace?

 

[foodfisher]

Re: force dying out on high throttle as time goes on oil mix? octane?

Check for fouled plugs

 

[ddrieck]

Re: force dying out on high throttle as time goes on oil mix? octane?

I second the card rebuild. It is a very basic carb and with a little patience and good Force repair manual you should be able to get it done. As for tools, you just need a few basic hand tools and a couple cans of a good carb cleaner. Be sure to flush out every single orifice in the card and follow the manufactures recommended settings for the float. Count the number of turns it takes to lightly seat the air mixture screw(clockwise) and rest to that setting for a good starting point when you refire the engine. After that you should do a link and sync to make sure the timing is dead on correct. You may need to have a mechanic help you out with the timing link and sync.

 

[shytownborn]

Re: force dying out on high throttle as time goes on oil mix? octane?

one thing you might wanna check is your fuel pump diaphram, with a torn diaphram the pump can keep up with the low demand for fuel, when cruising at low rpms, but then go to wot it will use the fuel in the carb bowls and then start to die out because the pump cannot keep up with the fuel the motor needs to go wot. then when you throttle down the pump will again fill the carb bowls and start the process all over again good luck don

 

[compute42]

Re: force dying out on high throttle as time goes on oil mix? octane?

Ok task for tomorrow is fuel pump, the previous one has ALL sorts of flakey white stuff floating around in it when I tap the side. yuck... Hoping thats it... tank did get run dry last time maybe it picked something up.

I'll check the fuel diaphram as well, if not then I'll pop the carb, and give it a quick cleaning...

 

[john from md]

Re: force dying out on high throttle as time goes on oil mix? octane?

While you have the fuel pump off, push lightly on the center poppets of the check valves to see if they are sticking. If they are sticking, the engine will die slowly at higher speeds. When they go bad, you will usually find that your fuel bulb has gone soft.

John

 

[compute42]

Re: force dying out on high throttle as time goes on oil mix? octane?

Strangely enough a new fuel fliter and a little more carb cleaner cured the problem thanks for all the suggestions!