engine loses power after short run

[siusaluki23]

1970 johnson 60 electric shift

it will run fine for a short while and then it will slowly lose power. , then it will surge like it is wanting get going.IF i idle for a little bit it will run well for a short while and then slow down again. carbs are clean and i beleive just rebuilt. compression 150 135 130. vent on gas tank is open, bulb is hard, i don't see the lines going flat. i have spark on all three cylinders.

my guess is my fuel pump i ordered a rebuild kit and will install it tomorrow.

 

[hamburgerman]

Re: engine loses power after short run

Have you changed your water pump lately? sounds like one I had that was getting hot warning buzzer did not work.

 

[siusaluki23]

Re: engine loses power after short run

i will start it up, idle out of the no wake zone and i get on it, runs good and slowly slows down. my thoughts were ther fuel pump is able to keep up at idle and when i go to higher rpm the carb bowls are drained and then th fuel pump can't supply enough fuel. when i bring it back to idle for a few seconds and go wot it runs good and then slowly loses power.

haven't changed impeller, but it will pull water level down in a barrel and i am afraid to run it on muffs. I believe that it is either an eletrical( ignition stator) or a fuel problem.

 

[tashasdaddy]

Re: engine loses power after short run

check your spark when it does it, could be a coil failing. could be clogged high speed jets, could be fuel pump. you have to start eliminating. spark is the easiest.