1988 60 hp Ignition diagnosis

[2manytoys81]

I am chasing a no spark situation on two of the three cylinders. The motor has been in storage for over 10 years, but it was running fine when put up. With the motor setup to run I only get spark on #3 cylinder. 1 and 2 have nothing. If I swap the green wires coming from the switch box I can get fire from each of the coils but only with the #3 wire coming from the switch box. Is there any other tests I can do to be sure its the switch box before I purchase one?

 

[ray914]

Re: 1988 60 hp Ignition diagnosis

I just went through the headaches your going through. I know this sounds real stupid BUT I took a small ball peen hammer and tapped on the corner (not hard) and if I didn't have a witness I would not tell this but it started working on all 3 cylinders. The bad part it ran great for the next couple of days and then nothing at all. I replaced the switch box and no more problems. This might help but good luck.

 

[2manytoys81]

Re: 1988 60 hp Ignition diagnosis

How does the switch box know when to signal the coils to fire?

 

[ray914]

Re: 1988 60 hp Ignition diagnosis

I don't know for sure but I'd bet the trigger assembly under the flywheel and the stator is it.

 

[zorak]

Re: 1988 60 hp Ignition diagnosis

Take some advice and do some testing before you start throwing parts at it.Do a search on this forum on how to build yourself a DVA adapter or buy yourself one.That in conjunction with an ohmeter and a search on this forum for the testing procedures will get you started in the right direction.There ain't nothing worse than spending a couple of hundred bucks on a part and it doesn't fix it. It gets really expensive really quick and most of the time no matter where you buy the parts they usually won't take returns on electrical parts.

 

[CharlieB]

Re: 1988 60 hp Ignition diagnosis

Stator generates the electricity

Ignition module stores it

Triggers tell the module when to send the electric current to fire the coils.

Disconnect the yellow leads to the rectifier and retest for spark, a bad rectifier can cancel spark on a couple of cyl's. If it now sparks on all 3 then replace the rectifier.

Then if still no spark, disconnect the black wire with the yellow trace line from the ignition module and retest, if still no spark then DVA TEST the triggers, and DVA test the Stator.

 

[2manytoys81]

Re: 1988 60 hp Ignition diagnosis

Stator generates the electricity

Disconnect the yellow leads to the rectifier and retest for spark, a bad rectifier can cancel spark on a couple of cyl's. If it now sparks on all 3 then replace the rectifier.

Then if still no spark, disconnect the black wire with the yellow trace line from the ignition module and retest, if still no spark then DVA TEST the triggers, and DVA test the Stator.

I will try these. I have checked the triggers according to the manual and their ohms are within range.

If the stator is not producing energy, would it be possible to get a good spark on only one cylinder?

 

[ajgraz]

Re: 1988 60 hp Ignition diagnosis

I will try these. I have checked the triggers according to the manual and their ohms are within range.

If the stator is not producing energy, would it be possible to get a good spark on only one cylinder?

Resistance testing is only one indicator; stator, trigger or coil can pass resistance test but still be bad. That's why you need the DVA adapter to check actual voltage outputs, as suggested above.

If the stator was bad, I'd expect that you'd get weak or no spark on ALL cylinders.

 

[shankforce]

Re: 1988 60 hp Ignition diagnosis

I think if you had the manual and ran the test for the ignition system you will find your stator to be weak. But I would change the rectifier no matter what. It is going to be in your power pack or stator. Usealy with the stator its no spark or very weak spark.

 

[CharlieB]

Re: 1988 60 hp Ignition diagnosis

There are a number of things that can cause spark on only one cyl.

1) a partially grounded kill wire, disconnect the black wire w/Yellow trace from the ignition module and retest spark.

2) a bad rectifier, disconnect and tape off BOTH yellow wires from the stator that connect to the rectifier and retest spark.

3) slow cranking speed below the minimum 300 RPM, attach an inductive tach to the sparking plug wire and test RPM, if below 300 RPM, recharge battery, clean BOTH ends of both battery cables AND the starter to relay cable, if still slow clean/repair starter, then retest spark.

4) DVA test triggers

THEN you DVA test the stator, but I doubt if it fails.

Usually a good spark on any cyl is a sign of a good stator.

 

[2manytoys81]

Re: 1988 60 hp Ignition diagnosis

There are a number of things that can cause spark on only one cyl.

2) a bad rectifier, disconnect and tape off BOTH yellow wires from the stator that connect to the rectifier and retest spark.

I removed the yellow wires from the rectifier and now have a good spark on all cylinders. Thanks a bunch. I never would have thought that the rectifier would have caused no spark on two cylinders. Plus its a cheap fix!

 

[shankforce]

Re: 1988 60 hp Ignition diagnosis

Rectifier goes alot on these mercs I have replaced them a few times. Very cheap fix.