40 hp 402 with a mind all its own

[joe79]

I am trying to work out an electrical problem on my motor, it will start up and run just fine, idle up just fine, full throttel and idle. After about 20-thirty min i loose all spark for a couple hours till its cold again then it will do it all over again cant seem to figure it out, and where can i look to find elect. specs. so i know what the acceptible ohms are for all the componets can anyone help

 

[Faztbullet]

Re: 40 hp 402 with a mind all its own

Go to CDI electronics and download the troubleshooting manual as it has all the spec's you need. If sounds like the stator is failing.....

 

[joe79]

Re: 40 hp 402 with a mind all its own

i tried the website and all the info is for newer motors and mine is an early 70's is the info still aplicable

 

[Faztbullet]

Re: 40 hp 402 with a mind all its own

The 40 & 402 only used 2 types of stators and here are links to test them...
http://www.cdielectronics.com/InstallSheet/174-5255.pdf
http://www.cdielectronics.com/InstallSheet/174-4424.pdf

 

[johnson20]

Re: 40 hp 402 with a mind all its own

I had same motor that ran for 15mins and stopped... in my case it was the trigger plate... oem meter test it when it cuts off.. only 2 wires

 

[joe79]

Re: 40 hp 402 with a mind all its own

I had same motor that ran for 15mins and stopped... in my case it was the trigger plate... oem meter test it when it cuts off.. only 2 wires

Would you happen to rember the specs on the trigger plate

 

[joe79]

Re: 40 hp 402 with a mind all its own

Go to CDI electronics and download the troubleshooting manual as it has all the spec's you need. If sounds like the stator is failing.....

i tried to ohm everything out, trigger and stator, this is what i came up with


trigger called for 140-160 meter read 827


stator blue to ground meter read 5.63 called for 5200-7400
red to groung meter read 50.4 called for 180-340

and couldnt find anything on the switch box or rectifier

can someone help me make sence of this

 

[vupilot]

Re: 40 hp 402 with a mind all its own

I also have a Merc 40 402, a 1975 model that began similar issues last fall. It runs perfect when cold for about 10 minutes then it begins to stumble at anything more than 1/4 throttle. After it cools off it runs pefect again, for a few minutes. The last time out it literally died completely 10 ft from the dock. After 30 min it started back up and we got it on the trailer in a hurry and I winterized it to deal with it this spring.

I will begin troubleshooting my motor when the weather warms up next month so I will be very interested in what you find on your motor. I guess I can rule out the fuel system after reading this so that helps.

Thanks for any info you can provide. I have the Seloc manual for this motor if you need me to look up any info.
Chris

 

[joe79]

Re: 40 hp 402 with a mind all its own

I also have a Merc 40 402, a 1975 model that began similar issues last fall. It runs perfect when cold for about 10 minutes then it begins to stumble at anything more than 1/4 throttle. After it cools off it runs pefect again, for a few minutes. The last time out it literally died completely 10 ft from the dock. After 30 min it started back up and we got it on the trailer in a hurry and I winterized it to deal with it this spring.

I will begin troubleshooting my motor when the weather warms up next month so I will be very interested in what you find on your motor. I guess I can rule out the fuel system after reading this so that helps.

Thanks for any info you can provide. I have the Seloc manual for this motor if you need me to look up any info.
Chris

If you could get me the factory specs to ohm out the stator and trigger I would be greatful.

Just a tip check your wiring. When mine started acring up I got to looking the insilation on all....all the wires was falling off and things were grounding out every where now I trying to figure what it burnt up

 

[vupilot]

Re: 40 hp 402 with a mind all its own

OK,

1972-1978 402. Thunderbolt Stator test. "Stator leads/coil wires must be disconnected before testing."
Leads between red and blue coil wires.
OHM scale= Rx100. Reading= 50-64

Trigger. "Leads must be disconnected before testing."
1972-78, 402
Tester leads between trigger leads
OHM scale= Rx100. Reading= 8-10

Hope that helps. Keep me posted.

At first glance all my wiring looks in very good condition but I havent taken anything but the cowl off yet so I cant see the wiring above the head.

-Chris

 

[joe79]

Re: 40 hp 402 with a mind all its own

sorry for the slow reply i have taken the motor off and stored it till i can come up with the extra funds to start putting parts on it
also since you have unhook everything im assuming it will test just fine with it in storage like that since its not hard to get to