1985 60 hp johnson motor(PLEASE HELP)

vik 44

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Sep 5, 2010
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The motor starts and idles ok but when on the water at 30mph the engine will drop to 7 mph all of sudden and will not pick up speed.if i release the throttle it and engage it again it jumps up and boggs back down to 7mph.when crusing at 7mph if i push the choke in it struggles but picks back up.is this a float issue,spark problem or just a carb problem with the jets.the carbs were taking apart and cleaned but i dont know if my buddy did a great job or not should i do a carb rebuild i am stuck please help
 

HighTrim

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Re: 1985 60 hp johnson motor(PLEASE HELP)

Did he remove the high speed jet and thoroughally clean it? Ill bet not. Check out the FAQs for a thread that will help you with this.

Also couldnt hurt to bring an inductive timing light with you to ensure that you arent losing spark on a cylinder while underway.
 

vik 44

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Re: 1985 60 hp johnson motor(PLEASE HELP)

Chris thankyou for the link alot of great info, quick? To remove the high speed jet is that the special tool you need to take the jet out? When he cleaned the carbs he did blow air through everything and ran a wire through the jet would that be good enough or does he have to use that tool and take both jets out completely?
 

Joe Reeves

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Feb 24, 2002
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Re: 1985 60 hp johnson motor(PLEASE HELP)

Unlikely it's a carburetor problem. Carburetors do not come and go, they're either fouled or they're not. The fact that you do obtain full throttle at first indicates that they're functioning properly.

Does the fuel primer bulb have a tendency to go flat when this problem takes place?
 

vik 44

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Re: 1985 60 hp johnson motor(PLEASE HELP)

yes the fuel ball always to me seems flat and never gets real hard
 

Joe Reeves

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Re: 1985 60 hp johnson motor(PLEASE HELP)

When I say "Go Flat", I mean that the primer bulb originally has its normal shape at first, then as the engine runs, the bulb actually starts to compress by itself. If this is what happens, you have a fuel restriction between the bulb and the fuel supply. If, on the other hand, the bulb is retaining its original shape and is just simply not full of fuel, that is a normal condition.

The fuel primer bulb should get quite hard when priming. If the carburetors are not flooding (which should be obvious), check to make sure that the VRO pressure line is not feeding fuel to the crankcase. If these two areas are okay, it might be good to purchase a new primer bulb to avoid further problems.

If the change in rpms is sort of gradual, that would indicate a fuel problem. If the rpm change is instantaneous like turning a switch on or off, that would be ignition. Which scenario is taking place?

Spark plugs should be Champion QL77JC4 plugs, gapped at either .030 or .040 . One gap or the other may provide improved performance. Are you using these plugs, and what do your plugs look like (brown, black, fouled with metal, dry, wet)?

Compression should be 100+ psi and even on all cylinders. What are your readings?

Spark, with plugs removed, should jump a 7/16" gap with a strong blue lightning like flame... a real SNAP! Does it? Note that using spark plugs to test the spark is a waste of time, the 7/16" gap is important.

Let us know what you find.
 
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