91 Johnson 60HP kicks while it cranks

[glachiew]

I bought a bass boat with a 1991 Johnson 60HP two weeks ago. It started, idled and ran just fine out of the marina and initially ran fine at full throttle. After 3 minutes it bucked violently, then recovered, then bucked again. It continued doing this the rest of the day, no matter the throttle setting. I had the power pack changed at the shop and it has a couple of problems that it didn't have previously.

1. It bucks and pops the steering wheel when I try to turn over the engine.
2. Once it fires up, it will only "idle" when the throttle is significantly advanced, not in the neutral position.

My shop is only open Tues-Thurs in the winter so that's why I'm asking now.

What would cause the popping on the steering wheel while cranking? When it fires up it's definitely in neutral.

Thanks!

 

[steelespike]

Re: 91 Johnson 60HP kicks while it cranks

You might have water in a cylinder. Check the plugs for signs of water.
Crank it with plugs out and the gas unhooked.It may have a little water spray out the plug hole.
You might do a compression check.Sometimes the plug will be very clean if water gets in the cylinder.
You'll need to be on muffs or in the water if your going to test for water.
If a flywheel key is partially sheared might cause it to buck.
There is a slim chance the plug wires may be worn and sharing spark if touching together.

 

[boobie]

Re: 91 Johnson 60HP kicks while it cranks

Check all the wires going to the power pack for being loose. Also check the power pack ground wire.

 

[glachiew]

Re: 91 Johnson 60HP kicks while it cranks

Thanks Steelespike and boobie. I did the easy thing and double-checked all the wiring to/from the power pack, including grounds. That was my first inclination too.

The plug wires all look great. The spacing was fine. The motor itself is sparkling clean, well maintained. I did move all the wires looking for abrasion on the jackets, etc. I'll take a look at the flywheel key tonight when I get it in the garage. It was already dark last night when I got this thread.

Thanks for your assistance!

 

[phillnjack2]

Re: 91 Johnson 60HP kicks while it cranks

sometimes it can be good to have a look under the hood in the dark.
its suprising how many sparks can show up that you dont normally see.
ive often thought an engines wiring was good and well protected from grounding etc, untill ive seen
it at night then it looks like a chritmas tree flickering.

when the engine starts it can be normal to see the sterring wheel jolt quick,especialy if you have
very free and easy steering.
i get this on 30hp and 60hp due to the torque of the engines when starting.
this also happens on the engine stands all the time unless you do something to hold the engine.


phill..........

 

[Charlie in TX]

Re: 91 Johnson 60HP kicks while it cranks

Compression numbers? That is about the first thing to do on a 2 stroke.

 

[glachiew]

Re: 91 Johnson 60HP kicks while it cranks

phillinjack

You had a good idea about running it in the dark. When I did I saw the strangest thing. I saw spark glowing around the lower plug. I made sure the plug wires were on tight and cranked again - same thing. Then I switched the plug wire with the cylinder above it and saw the spark glowing in the same place! It did not follow the wire?! Then I changed the spark plug and it still glowed.

This makes no sense to me.

 

[Will Bark]

Re: 91 Johnson 60HP kicks while it cranks

Could it be rusted or corroded plug connections up in the plug boot?

 

[glachiew]

Re: 91 Johnson 60HP kicks while it cranks

Problem solved. It turns out the repair shop cossed the two longer wires coming off the power pack that went to the two upper cylinders. Runs fine now! Whew!

Thanks everyone.