1986, 125HP: Carb or Electrical Problem?

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sjdwallingford

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Boat stalls at idle and now is sporadic in acceleration and is not reaching top power. Boat was running fine last week. I rebuilt the carbs this spring and the engine has never run better until now . . .

The engine stalls at idle. I changed the spark plugs. Didn?t help. It seemed to me that idle was too slow, so opened up idle screws a bit. No change. In fact, the engine seems unresponsive to adjustments of the low speed jet.

I attempted to avoid the problem by adjusting the idle position of the throttle. This kept the RPMS high enough so I could put engine in gear. Engine sputtered, but cam up to speed.

After a pulling a water skier a few times, engine was having problems coming up to full power. At this time, the engine will not reach full power. I suspect I'm not firing on all cylinders.

I was going to take the carbs off and clean them, however, the fact that the idle screws have no effect on the engines RPM makes me think it's not a fuel issue but an ignition issue. Any comments welcome. Thanks.
 
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sjdwallingford

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Re: 1986, 125HP: Carb or Electrical Problem?

One more bit of information: I put a spark plug light on each spark plug and the light flashed for all plugs, indicating that plugs are getting juice (plugs are new). Not sure if this is conclusive though--i.e., could I have a low voltage situation with a deteriorating coil, or does the coil usually just fail with no output at all. Thanks.
 
fucawi

fucawi

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Re: 1986, 125HP: Carb or Electrical Problem?

you would not notice much difference if winding out the idle mixture screws ..these are not the idle speed screws..you should wind them in until the revs peak ..if you go too far in it stumbles and stops as the mix gets too weak....First base is to look to your idle speed of about 750 rpm
 
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ben jones

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Re: 1986, 125HP: Carb or Electrical Problem?

sjdwallingford said:
Boat stalls at idle and now is sporadic in acceleration and is not reaching top power. Boat was running fine last week. I rebuilt the carbs this spring and the engine has never run better until now . . .

The engine stalls at idle. I changed the spark plugs. Didn?t help. It seemed to me that idle was too slow, so opened up idle screws a bit. No change. In fact, the engine seems unresponsive to adjustments of the low speed jet.

I attempted to avoid the problem by adjusting the idle position of the throttle. This kept the RPMS high enough so I could put engine in gear. Engine sputtered, but cam up to speed.

After a pulling a water skier a few times, engine was having problems coming up to full power. At this time, the engine will not reach full power. I suspect I'm not firing on all cylinders.

I was going to take the carbs off and clean them, however, the fact that the idle screws have no effect on the engines RPM makes me think it's not a fuel issue but an ignition issue. Any comments welcome. Thanks.
Click to expand...


I just had a similiar problem with my 75 hp. it was running fine when i start it for about a minute then it wouldnt hold any rmps and would want to chug and die. The idle screw did nothing, the carb screws did nothing. Im scratching ,my head wondering what the hell the problem was because i just replaced the plugs and wires and the trigger the coil and the cd are fine too, so what could it have been??? The damn bottom carb fell out of sync with the other two somehow so when it slowed a little at idle the bottom carb was at about 1/4 throttle while the other two were shut. Its always something simple once you figure it out.
 
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sjdwallingford

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Re: 1986, 125HP: Carb or Electrical Problem?

ben jones said:
I just had a similiar problem with my 75 hp. it was running fine when i start it for about a minute then it wouldnt hold any rmps and would want to chug and die. The idle screw did nothing, the carb screws did nothing. Im scratching ,my head wondering what the hell. Tthe problem was because i just replaced the plugs and wires and the trigger the coil and the cd are fine too, so what could it have been??? The damn bottom carb fell out of sync with the other two somehow so when it slowed a little at idle the bottom carb was at about 1/4 throttle while the other two were shut. Its always something simple once you figure it out.
Click to expand...

This is very interesting I have two questions:
1. While you had this problem were you able to come up to full power? I.e., was the problem on at idle?
2. Did you fix it just adjusting linkage?
 
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