Calling all Inline Six Gurus

[L115]

Once again thanks to everyone contributing here.

This coming Tuesday, the engines will finally be back for the service needed to solve the problem.

Regarding flywheels, I have checked the Mercury part numbers on BOATS.NET and discovered that the Distributorless models of the 115, 1980-1983 did indeed use a red flywheel #5977A28. The later models, 1984-1988 have both a different stator number and a different flywheel number, #8722A7, which is olive green in color. My engine is a 1984, and I now have located and purchased an excellent used one of the correct part number. So this would be why the red one fits the engine, but is not correct, assuming there MUST have been some reason Mercury changed these, and applied a different color to distinguish it from the prior wheel.

The major change in these engines between 1983 and 1984 was the modern bracket mounted power trim system was installed. So I'm wondering if that is what initiated the engineering need for a different wheel & stator. Who knows, but I do know the stray current is coming off this engine, and only when it is running. There must be some sort incompatibility between the red flywheel magnets and the stator. This engine is also the one with the gearcase housing being eaten up by the galvanic action. Fortunately I discovered the problem almost immediately, and I think the corrosion can be easily repaired, but will require repainting and minor filler work in pitted areas.

It will be about a week and a half before I retrun from this vacation and will be able to report results and findings. I am printing up the entire discussion for the service tech (who is the business owner) to reference.

All comments are greatly appreciated. This is great site. You Checkmate owners and fans are knowlegeable boaters and it is a pleasure to participate! I will be looking for Checkmates out on the water now that I have become familiar with the site.

 

[Bill Gohr]

Once again thanks to everyone contributing here.

This coming Tuesday, the engines will finally be back for the service needed to solve the problem.

Regarding flywheels, I have checked the Mercury part numbers on BOATS.NET and discovered that the Distributorless models of the 115, 1980-1983 did indeed use a red flywheel #5977A28. The later models, 1984-1988 have both a different stator number and a different flywheel number, #8722A7, which is olive green in color. My engine is a 1984, and I now have located and purchased an excellent used one of the correct part number. So this would be why the red one fits the engine, but is not correct, assuming there MUST have been some reason Mercury changed these, and applied a different color to distinguish it from the prior wheel.

The major change in these engines between 1983 and 1984 was the modern bracket mounted power trim system was installed. So I'm wondering if that is what initiated the engineering need for a different wheel & stator. Who knows, but I do know the stray current is coming off this engine, and only when it is running. There must be some sort incompatibility between the red flywheel magnets and the stator. This engine is also the one with the gearcase housing being eaten up by the galvanic action. Fortunately I discovered the problem almost immediately, and I think the corrosion can be easily repaired, but will require repainting and minor filler work in pitted areas.

It will be about a week and a half before I retrun from this vacation and will be able to report results and findings. I am printing up the entire discussion for the service tech (who is the business owner) to reference.

All comments are greatly appreciated. This is great site. You Checkmate owners and fans are knowlegeable boaters and it is a pleasure to participate! I will be looking for Checkmates out on the water now that I have become familiar with the site.

Anytime a part is changed in any way, the part number changes, even if its just the color. The stator changed type of wire back in the early 80's so that would explain the number change, however all these parts are functionally interchangeable with any 6 cylinder engine, not to long ago I needed a stator for an ADI in line, didnt have one at hand so I modified the leads on a 260 Hi Perf stator and installed it onan 82'.

 

[L115]

Finally, I have an update. I have been using the boat for the last month in FL, and can report the problem is fixed, the galvanic corrosion problem gone.

I located the correct army green colored flywheel for the engine on Ebay and found one like new, and had the Mercury shop down in FL install it, removing the 1980-83 era red one. He also checked the same engine carefully and found a ground strap broken, which he replaced. So I guess I will never really know what solved the problem, but it's fixed. I still think it was the flywheel, but like some of the contributors here, the Merc shop owner/mechanic insists it was NOT the red flywheel he installed on an emergency basis a year ago. I've got to say he has good credentials, as he was racing the 125BP's with stacks in the late 60's and has been working on these engines ever since. He could rebuild one of these engines in his sleep, and knows all of the upgrades and improvements Mercury put into them over the 30 years they were being manufactured.

I should also mention that while the red flywheel was on the engine, the engine blew out two brand new rectifiers, and two voltage regulators. It also ruined a brand new battery with only 20 hours of engine charging before it failed. The battery manufacturer gave me a new one free. All of those problems have since disappeared also.

Once again, thank you to all who contributed.

 

[DropTop5.0]

Larry - Great to hear that the problem is solved and of course we'll want pics.