175hp 1995 Johnson losing power at 2000rpm

[Anthony Lilley]

Boat has run excellent for several years. I had a mechanic change the throttle and gear change cables after the boat sat for 2-3 mths over the winter. On my 1st run, it would not plane. It fell on its face at around 2,000 rpm. Took it out of the water and it runs great under no load. I told the mechanic to check the power pack grounding, since this was an issue several years ago. He said he checked that, replaced spark plugs, tried different coils and power pack and changed the stator, and some sensor (optical I think) on top of the motor. He also said that the 3 spark plugs on the right side had no spark. I'm at witts end... anybody have a suggestion? It seems we have checked everything?

BTW - I'm not convinced that the problem is not a grounding issue. I think I am going to go to the mechanic and ask them to remove the power pack and let me see the piece of metal that goes inbetween the power pack and the motor - this was my problem before, it had rust on it and created a bad ground.

Thanks for any suggestions.

 

[R.Johnson]

Re: 175hp 1995 Johnson losing power at 2000rpm

If the engine has one, no spark on the right bank suggest's a shift assist switch. I no longer have that manual, but that would be my guess. I would be leary of a mechanic that changes that many part's with no result's. Does he have the proper service information, and test equipment. Does he have any training. Should be a certificate somewhere around that shop if he does.

 

[Anthony Lilley]

Re: 175hp 1995 Johnson losing power at 2000rpm

Shift assist switch is an excellent idea!! I have a manual and will locate it. Could they have somehow caused the problem when they changed the shift and throttle cables?
TX
The mechanic actually normally does pretty good, they have 3-4 mechanics on staff, but the guy that worked on it this time looked like a neanderthal.

 

[R.Johnson]

Re: 175hp 1995 Johnson losing power at 2000rpm

Yes! There is an adjustment to that switch, and shift cable. They must be in sync, or that switch will ground out the right bank. That switch would be located lower down by the shift linkage. If the engine has that switch, for now just disconnect the wire, and see if the spark come's back.

 

[jonesg]

Re: 175hp 1995 Johnson losing power at 2000rpm

Shift assist switch is an excellent idea!! I have a manual and will locate it. Could they have somehow caused the problem when they changed the shift and throttle cables?
TX
The mechanic actually normally does pretty good, they have 3-4 mechanics on staff, but the guy that worked on it this time looked like a neanderthal.

you could do a better job yourself with major savings just by using this resource at iBoats and a bit of common sense in the troubleshooting dept.

 

[Anthony Lilley]

Re: 175hp 1995 Johnson losing power at 2000rpm

Problem solved. Had the boat out this weekend running like a champ!! It was a grounding issue - mechanic said the stator was not grounding well. My stator had some damage from overheating, so I had them replace it with good condition used one. This did not fix the problem. They took the stator, power pack and coils off again, checked all the grounding and put it all back together and it started working. Cost me $340, and it was in the shop for a month. Not worth it - I could have fixed this myself. Thanks for the advice.