'97 Johnson 175 Stalling in the Mid-Range-HELP

[HS91_Mike]

A '97 Johnson 175 Ocean Runner was bogging down this past weekend when offshore. It ran fine going out and problems occurred when powering up to come back in. No cranking problems. When I showered down on it to take off, the engine would bog down and die. If I slowly increased RPMs from 1000to 4000, the engine did not bog or die, but did not feel like it had full power. Also, when I slowly increased RPMs, the engine would sort of struggle and then at about 3200, would take off. I dont know if anyone is familiar with 2-cycle dirt bike engines, but it reminded me of a power band kicking in. It ran fine on the top end (3800+ RPMs).

I dont know if it is related, but it also started sputtering and dying at idle and when trailering and anchoring. This has been an on again off again situation. A mechanic told me that is just the way Johnsons are.

Any ideas?

 

[jonesg]

Re: '97 Johnson 175 Stalling in the Mid-Range-HELP

Sounds like fuel delivery, I would test again by spraying fuel mix into carb throats to see if it picks up on acceleration.

If yes
rebuild the carbs with new kits, simple DIY project.

if no,
pump the bulb whilst throttling up.
If that helps then look at the pump.

Also test throttle advance components on the flywheel aren't getting stuck or binding, acceleration relies on ig advance moving smoothly.

 

[jwellcraft]

Re: '97 Johnson 175 Stalling in the Mid-Range-HELP

Well said jonesg and HS91_Mike make sure your warning horn is working and the fuel vacuum switch is good because it will alert you of fuel starvation and the horn will alert you of other probs if they occur.

 

[HS91_Mike]

Re: '97 Johnson 175 Stalling in the Mid-Range-HELP

Thanks jonesg and jwellcraft,

I know the issue is not a fuel starvation problem. The fuel delivery system is new from from the tank to the fuel pump minus the pick-ups, which are in good shape. Had a previous problem with the anti-syphon valve and replaced that. The primer bulb stays full/firm at all times - idle to WOT.

I am leaning towards the carbs and clogged jets. I had the engine re-built last year and the mechanic rebuilt the carbs as well. The fuel pump was not replaced, but everything else was. Since then, I have had one throttle plate stick and the issue with the the check valve (which is now gone). In the past year I put less than 50 hours on the engine and I think that I am already having carb problems. Is this normal?