1992 60hp Johnson issue

Hey guys and gals....been awhile since ive posted but here is my issue....I have the above engine on my boat and everytime i put in the water and throttle up to full speed the engine will slow down to a fast trolling speed and continue at that speed for about 15-20 min and then take off like a rocket and be fine for the rest of the day....it idles smooth, never bogs down and no hiccups in the sound of the engine running....compression is good ....im thinking it may be a relay of somewhat or something electrical not the fuel as it runs very smooth.....thanks

Almost sounds like the high speed orifice is partially plugged.
Have you tried using some Sea-foam mixed in the gas & fogging the carb with Sea-foam.

No I have not as I dont think its a fuel/carb issue as the motor runs as smooth as can be .....idles perfect.....

If fuel is getting through the low speed orifice fine it will run smooth at low speeds.
When you speed up the high speed orifice opens up. If there is a restriction here the motor will not jump up to speed but run slowly.

I have the same motor but its the Evinrude version. I've had a ton of issues with air leaks at various locations in the fuel line. Normally this lets you run at trolling speeds but it would die out at higher speeds. I'd spend half my time on the water squeezing a soft primer bulb. So this could be a place to look.

been there done that....bulb hard not starving for fuel

I have the 1988 version of the 60 HP. I run only premium gas without ethanol in it and add sea foam to every tank. When you get your premium gas, (Canadian Tire sells premium without ethanol) pump the first 10-12 litres into your car then fill your boat gas tank or jerry can. If the last person to use the pump, pumped regular gas then the first 10-12 litres already has regular gas in the combined piping system.

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Originally Posted by Rick in Muskoka

I have the 1988 version of the 60 HP. I run only premium gas without ethanol in it and add sea foam to every tank. When you get your premium gas, (Canadian Tire sells premium without ethanol) pump the first 10-12 litres into your car then fill your boat gas tank or jerry can. If the last person to use the pump, pumped regular gas then the first 10-12 litres already has regular gas in the combined piping system.

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Wow, I never would have figured that there was that much fuel in the lines before getting what you actually select to pump. Good to know. Tks.

Cheers

I would think that 3 to 4 litres is enough to clear the line.

Gotta go +1 on the high speed jet.

How many times has it done this? Once, or more than Once?
Once? Fuel issue.. most likely a plugged jet

More than Once.. electrical issue.. my guess is the power pack or a bad coil

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every time i launch the boat for the past 3 years...that initial throttle down goes great...get up on plane go for about 3 minutes and then motor just slows down to a fast trolling speed...after about 15 minutes at this speed with throttle wide open it gives a little knock and away we go and runs great for the rest of the day...starting and stopping......i just had a coil and the power pack replaced along with new plugs 2 weeks ago....took it out ran great...started and stopped a few different times no issues.....fired the boat up to go in and as soon as it started it was running like ...very rough and couldnt get it to move except for a trolling speed all the way in.....checked plugs and 2 out of the 3 seemed to be fouled im hoping....cleaned them up after i got home and hoping to get out this wkd to see if that was the issue

If 2 out of 3 new plugs are fouled there is a reason.
Still think your dealing with a fuel issue.
Try Seafoam.
A fairly cheap thing to try. It sure can't hurt.

It turned out to be another bad coil.....the middle cylinder wasnt firing at all and turned out to be the coil he replaced went on me after only a morning of running......he replaced free of charge.....i also put seafoam in my tank.....trying to get it out now and give her a good run