40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

[spyeoman]

Hi, still trying to get this yam. going. It will usually run on just #3 cyl. When I unplug the thermo switch wires, #2 cyl. will also begin running. The top #1 cyl, never kicks in. After plugging the thermo switch wires back together it will often times run on #2 cyl. but not #3 cyl. anymore.
I bought a new CDI for $430, it didn't fix the problem. So now I'm a little disappointed and hoping for some advice. Does a bad thermo switch shut down entire cylinders on these models? I'm going to test the thermo switches today, I believe this motor has two thermo switches, they look the same and one is just above the other. I can unplug either one and usually get another cyl. to start firing. The results are not alway consistent.
Thanks, Steve
It's been out on the water, I'm bringing it home to the yard today so I can work on it until it runs.

 

[spyeoman]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

just cecking the post, hoping for advice.

 

[kandil]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

do you have a good manual? you need to trouble shoot the electrical system before you buy any part the shop manual have step by step trouble shotting direction and tools you will need to perform the task good luck

 

[JUSTINTIME]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

test the coils first and the wires

 

[spyeoman]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

Thanks guys,the shop manual and the tests would be great, I'd have to learn more than my basic voltmeter skills, which wouldn't be bad.
Each coil is delivering spark, pulling a boot of each cyl. when the motor is running gives a shock half way my arm. I've switched them around to different cylinders and found them to work.
It's going to run and be a great motor, I just have to keep experimenting or pay a pro. but I think I'll get it.

 

[JUSTINTIME]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

u need a good meter and a dva to test things
it could be the carbs or fuel pump

 

[spyeoman]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

i worked on the motor a little while, it seems that the top cylinder is my real problem #2 and #3 are running. the top cylinder just pops every now then, sounds like a coughy, pop. it doesn't sound like it's trying to go. plug tip is sparking away nicely. that's my latest, thanks, spyeoman.

 

[Dunaruna]

Re: 40HP '93 MLHR 3cyl, Not running on all cyl. Electrical Prob.

The wire connections for the coils and the wire connections for thermo switch(s) are VERY similar in appearance, they are also VERY close to each other.

Is it possible that you have inadvertently switch the connections?