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2000 Johnson 50hp Cutting Off at Low Speed

M

mercury25obx

New member
I apologize if this thread exists, I couldn't find it anywhere. It's striper season, so I am doing a lot of trolling and my 50hp cuts off going 3mph or less. Anything over this speed it runs just fine and it also idles fine. Other than rebuilding the carbs, are there are beginner adjustments that can be made to keep it from cutting off? It seems to be shaking and pissing intermittently when it is at that low speed.
 
Have you installed a new water pump impeller ?----As usual I recommend a compression test.----Post your numbers.
 
It’ll ride at 3mph for about 3-5 minutes, spits and quits is the perfect way to put it. It runs great at higher speeds and in idle. It’s just low speed in gear. I read elsewhere that maybe my carbs(2 on this motor) aren’t calibrated and that is why it shakes and does run right? The compression was fine last time I checked it.
 
Just did the compression this AM, 140-140 top-bottom. Of course when I try to get it to cut off, it won't, but it was shaking like crazy at low speed and just doesn't sound right. It idles like a champ, no shaking, good flow. Maybe it is something as simple as a linkage adjustment or rebuilding the carbs? Check out the video below, that was just morning.

 
The 2 cylinder looper is a shakey motor at idle, pump the bulb while trolling to see if it stops. Could be a weak fuel pump and carbs go lean...
 
mercury25obx said:
Just did the compression this AM, 140-140 top-bottom. Of course when I try to get it to cut off, it won't, but it was shaking like crazy at low speed and just doesn't sound right. It idles like a champ, no shaking, good flow. Maybe it is something as simple as a linkage adjustment or rebuilding the carbs? Check out the video below, that was just morning.

Click to expand...

That's a fair amount of shaking. All I can say is that the 9.9/15's do that if the idle mix screw isn't set correctly. I'd start with some carb tweaking.
 
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