35hp Merc Only Firing on #2 Cylinder

[a.lee.hagen]

So I've been having an issue as of late w/ the 35hp Mercury I've got attached to my '71 Boston Whaler. It won't fire on the #1 cylinder. I started with replacing plugs thinking it fouled one, not the case. I switched the coils and the problem persisted. Through the advice of the local boat repair shop I replaced the switchbox, found one on eBay for $80 because I didn't feel like paying $230 for one! The problem is still continuing to happen. I'm not sure where to go from here and any help would be appreciated.

Ground wires seem to be in good order. Through my work I did find a ground wire to the #1 cylider coil that was badly corroded and almost split in the middle and replaced that, but it did nothing to solve my problem. This thing is driving me crazy, it's not even my boat, it's the father-in-law's and we are keeping it/using it/taking care of it for him because he has another boat he uses more regularly.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

bump


anyone?

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

i would really appreciate some help here guys...

 

[oldgradywhite]

Re: 35hp Merc Only Firing on #2 Cylinder

Another mercury 35hp 5 th week lol. Check your coils for resitance, stator, and trigger. IF you have a dva you can run voltage check on all these parts. Jest had to replace the trigger and stator. What you are telling me more point to a stator but even more likey a bad coil.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

I have switched the coils and the problem persisted on the same cylinder though...

How do I check the coils for resistance?

What's a DVA?

 

[CDI Tech Support]

Re: 35hp Merc Only Firing on #2 Cylinder

I have switched the coils and the problem persisted on the same cylinder though...

How do I check the coils for resistance?

What's a DVA?

DVA Explained

Resistance is a highly unreliable measurement. DVA is a highly accurate measurement. But you must have a digital meter with a DVA Adapter attached.

Here's our troubleshooting guide for your engine:

Mercury 2 Cylinder - 339-7452

You've swapped ignition coils, so you've eliminated that.

Since you've replaced your switch box & the problem persists on the same single cylinder, the problem could be the trigger. DVA checks on the trigger per our guide could reveal the issue.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

thanks a lot for that info, can't look at .pdf's on my phone but i'll be sure to check it out when i get home on the laptop.

question, would it be dumb to just replace the trigger? and a ballpark on what one would cost?

 

[CDI Tech Support]

Re: 35hp Merc Only Firing on #2 Cylinder

question, would it be dumb to just replace the trigger? and a ballpark on what one would cost?

We always suggest doing the proper troubleshooting prior to replacing parts. However, no spark on a single cylinder typically rules out the stator, leaving the stronger possibilities as the switch box, trigger & ignition coil. Since you've eliminated the ignition coil & the switch box (assuming the replacement doesn't have the identical cylinder out), that leaves the trigger as the most likely culprit, if indeed it's a component. Be sure to check all wiring, especially grounds.

We still suggest doing the proper troubleshooting prior to replacing parts.

We offer Repair & Return only for that trigger. List price is $80 + return shipping.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

okay, next question... where is the trigger? and what does it look like?

 

[j_martin]

Re: 35hp Merc Only Firing on #2 Cylinder

okay, next question... where is the trigger? and what does it look like?

What are the odds that the switchbox you bought is also bad?

That's why we recommend getting set up with a proper meter, and a genuine maintenance manual, and going through the test procedure for your engine. That way you isolate the bad part before you buy anything. Believe me, it is the fastest, cheapest way to a repair.

If you have to ask where is the trigger, it's obvious you don't have or aren't using proper documentation.

hope it helps
John

 

[CDI Tech Support]

Re: 35hp Merc Only Firing on #2 Cylinder

okay, next question... where is the trigger? and what does it look like?

First, locate the switch box. From there, follow the Brown/Yellow & Brown/White wires. Your trigger is located underneath the flywheel, housed around the stator's frame. See attached pic (trigger is part# 14):

 

[CDI Tech Support]

Re: 35hp Merc Only Firing on #2 Cylinder

What are the odds that the switchbox you bought is also bad?

The odds of having a 2nd switch box with the same faulty cylinder are pretty low, but still possible. But yes, you are correct...he needs to have a qualified marine mechanic perform the trigger DVA checks per our troubleshooting guide.

That's why we recommend getting set up with a proper meter, and a genuine maintenance manual, and going through the test procedure for your engine.

We feel our Troubleshooting Guide is the most accurate & thorough 2-stroke ignition-related guide in the industry. In 28+ years, we've done far more research than the OEMs themselves.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

If you have to ask where is the trigger, it's obvious you don't have or aren't using proper documentation.

hope it helps
John

You're absolutely right. But I'm also trying to do this with limited knowledge of outboards. I do have some experience w/ cars and motorcycles and am just trying to do this thing by myself.

 

[a.lee.hagen]

Re: 35hp Merc Only Firing on #2 Cylinder

Okay, so say I pickup a Multimeter on CL for what they are going for right now, $75-$125. I then pickup the DVA attachment, not sure how much that is but it can't be cheap. I test the wires, it's the switchbox again, another $100 minimum assuming I can find one on eBay or other site. Or maybe it's the trigger, $100 after shipping. Or I can take it to a shop and pay $105/hour to troubleshoot my problem and have no work done and still have to shell out cash for the parts... how do I win?

 

[CDI Tech Support]

Re: 35hp Merc Only Firing on #2 Cylinder

Okay, so say I pickup a Multimeter on CL for what they are going for right now, $75-$125. I then pickup the DVA attachment, not sure how much that is but it can't be cheap. I test the wires, it's the switchbox again, another $100 minimum assuming I can find one on eBay or other site. Or maybe it's the trigger, $100 after shipping. Or I can take it to a shop and pay $105/hour to troubleshoot my problem and have no work done and still have to shell out cash for the parts... how do I win?

If it were my engine, if I didn't have DVA equipment, given what has already been diagnosed & given the odds of what remains to be diagnosed, I'd have the trigger replaced or repaired.

We do offer a service of testing parts. Check & Advise price on this trigger ranges $35-$40 + return shipping.

Repair & Return price is $80 + return shipping.

The $35-$40 price can be applied towards the $80 if the trigger is found defective, if you desire repair.

If interested, complete the following online form & once completed, click "Submit Query" at the bottom of the page:

http://www.cdielectronics.com/rma_request.asp

Once our Repair & Return Department creates a RMA for you, they will email you a RMA#. Please write that RMA# next to our address on the package.

Allow at least 10 business days in house for repair.