90 Force mid throttle cutting out and dying

[93nitro]

Thanks for the help on the impeller question I inquired about last week. Got it installed and it is working great. New problem is that it is starting hard, backfiring occasionally, and dying several times while trying to start cold. Took it out the other day and got going with it and about 1/3 throttle it dies out. I kept trying to get it to open up all the way without dying and it did once and took off like a rocket so I know it has potential and will run great when I get the bugs out of it. I checked compression and have 110 upper, 110 center, and 90psi on lower cylinder so compression is decent I believe. Any pointers? Is a blown head gasket possible? I have read about rebuilding the fuel pump. There is a white filter after the pump that I might try to change. Don't know anything about boat carbs but might try to clean them. Any thoughts from someone that would have better answers than my guesses? Thanks a million in advance.

 

[93nitro]

Re: 90 Force mid throttle cutting out and dying

Anyone have any ideas that are being overlooked? I Hope to work on the engine this afternoon but not sure what direction to head first. Thanks, Sean

 

[jerryjerry05]

Re: 90 Force mid throttle cutting out and dying

Get another comp tester.One that screws in.110# is low even on a cheap guage.
Do a de-carb.Powertune or Seafoam will help bring up the numbers if your guage is acurate.

Fuel pump,rebuild the pump.Carbs,they are easy to clean,just be sure that you re-assemble them right.Don't touch or adjust anything but the air screws.Got a manual?Get the factory one and read all about the carbs.
Ethanol is messing with the rubber and plastic.Any inline connectors,they can start to suck air.Jerry

 

[steveclv]

Re: 90 Force mid throttle cutting out and dying

Is it running happily at part throttle but not at high?

It could also be fuel starvation as another poster had so check the screen that is in between the brass fitting and aluminum pick-up tube in the fuel tank - mine was so caked up with varnish that I had to chip it off and the symptoms were fuel starvation at high rpm.

This seems to be one of the filters that no-one ever remembers and can cause problems at high speed.

 

[93nitro]

Re: 90 Force mid throttle cutting out and dying

I dumped some seafoam in the tank a couple nights ago but haven't got it in the water since. Getting ready to buy a factory manual as it appears they are the ones to get. Would like to clean the carbs for sure now. Jerry what do you mean by de-carbing it? Haven't heard of that before.
Starvation is another I was wondering about. I will check the entire fuel system when I tear into it. Thanks a bunch for the input guys!

 

[Tom3061]

Re: 90 Force mid throttle cutting out and dying

Let me know what you find out... I think I may have the same issues. Thanks!