1987 Merc OB 175HP V6 - Stator, Trigger, rectifier? One side V6 not firing - Stator # 398-5454-A36?

I have a 175HP Merc (1987), Serial # 0B168308 - I have been tracing down a problem with one side of the V6 Being dead, not firing all 3 cylinders. I have gone through the wiring check, switching the stator leads to the switch boxes (as well as switching the switch boxes to make sure they are both fine - which they are - I moved each to the opposite sides and the problem remained on the original problem side). When I switch the leads to the switch boxes the problem changes sides, originally 1, 3, 5 not firing, switch stator leads and 2, 4, 6 not firing. The CDI troubleshooting and manual says it is the stator.

Long story for this question. I took the flywheel off and the stator part number on it is 398-5454-A36, yes A36. I have owned this boat for over 10 years, so it has run very well before. My question is that the part # A36 does not come up in online search, Mercury express shows A7, A32 & A35 but I have rechecked the part # on the existing stator and it is A36 so I am not sure which replacement I need? Is it the A35, A32 or the A7?

With that question asked, I am not sure if the problem is the stator, trigger, rectifier or something else. I am pretty sure, with the tests recommended by CDI, that it is the stator. I am not a mechanical wiz but am not an idiot either and it seams like, logically, the stator is the problem due to the change of leads moving the problem from one side to the other. Do I just need the correct stator replaced or do I need to replace the trigger and or rectifier as well or is it just the flywheel? I don't think the flywheel as it is generating power with the stator it is just that one side of the stator leads is not pumping out the needed power. Do not have a DVI or whatever that meter is so I cant really test for the voltage output. Again everything I have read and done says it the stator. Now the A36 part number has thrown me another curve.

Any help would be greatly appreciated. I have a good history of the problem occurring but have made this post long enough already.

Use an ohmeter to check stator resistance and check resistance on the trigger coils.------------------Rectifier is generally considered to be part of the battery charging system and not part of the ignition system.

Those switchboxes are interchangable. If you switched the two and the problem followed, then you know it's the box. If the problem did not follow, then it's the stator. I vote for the switchbox. Lots of them on eBay for under a c-note.

Jeff

Thanks to both of you.

I know its not the switch box. I have swopped them and the problem stayed on the 1, 3 & 5. SO I am pretty sure its the stator.

Racerone, how do I check the resistance on the trigger and stator? What contact points do I test? I think the CDI troubleshoot list has some ohms ranges.

My real question is why does my stator on the boat say its an A36 and the Mercury website only shows the A7, A32 & A35 for my unit? Also I cant find the A36 on the web anywhere/ So which one do I replace it with the A32 or A35?

Thanks again,

Steve

The simple answer is ---------------They used A21-34-35 etc to identify small changes on the part or the factory they came from or the production run.---------Fair enuff question and fair answer.

Thanks racerone. I thought maybe the A36, A35 and so on where related to the amps produced, possibly. Glad to know it is more of just a part number and not the power output. I am not an electrician by any stretch but know from experience that the wrong amps can be bad for other parts in a big way.

Again how do I check the resistance for the stator and the trigger?

Steve

1987 Merc 175 OB said:

Thanks racerone. I thought maybe the A36, A35 and so on where related to the amps produced, possibly. Glad to know it is more of just a part number and not the power output. I am not an electrician by any stretch but know from experience that the wrong amps can be bad for other parts in a big way.

Again how do I check the resistance for the stator and the trigger?

Steve

Click to expand...

Steve I had the same problem Stator # 398-5454 A36 is a Sierra stator

Sierra stators do not have the Merc part number(398-5454 A36) they are a 18-XXXX number. OP...Your stator is bad from your testing

If looking for a new stator you should check the prices from CDI electronics (sold through aftermarket places like ebasicpower.com - maybe Andrew on this site has them as well - not sure).

Anyhow, I have found the quality of the wires on the CDI products to be superior in many cases to Merc OEM stuff - and (usually) cheaper on top of that - sometimes "alot" cheaper...

And yes, as racerone notes, the numbers after the A are simple production run numbers of essentially the same part. If the part is no longer interchangable they will list it as a new part number. So if all the numbers "before" the A are the same, it will work perfectly...

I use Sierra parts as they will pay me if parts fails and they have BEST warranty on the market....
Warranty Claims for Professionally Installed Products:
For any SIERRA product that was originally installed on a vessel by a dealer or other professional installer that fails to comply with the Warranty, in addition to repairing or replacing the product free of charge, SIERRA will also reimburse the customer for reasonable labor charges incurred to replace the product, and reasonable towing and other similar incidental expenses incurred as a result of the failure of the product to comply with the Warranty. Labor will be calculated based on the installer’s posted shop rate that is competitive with their local market rates. The original work order along with the original invoice and a copy of the new re-work order must be provided to SIERRA to file a claim for reimbursement of labor expenses. Towing charges will also be paid based on reasonable and customary rates in the local trading area. A copy of the original invoice for the towing service must be provided to SIERRA to file a claim for reimbursement of towing expenses.