2 simple questions, coils and model #

[BackyardKrazy]

OK, I am surfing around curious about a replacement coil for my 1989 125. What does it mean when they say A,B,C,D or E models? How do i know? i dont have a serial number, dont ask.... And I noticed Iboats dont have listing either?

Also whats the difference between blue and black coils?

 

[jerryjerry05]

The abcde is model changes.
Means they made a small change in something??

Don't worry about it.

Why do you think the coil's bad??
In 35 years I'v eonly seen 2-3 bad ones.
Try switching them around??
The trigger wires break under the shrink wrap and stop the plug/coil from firing.

The blue/black is nothing but the black was made later and you can use both at one time.

Is the 125 on the original boat?
Send the hull# to the maker and they can tell you the info.

 

[BackyardKrazy]

When I purchased the boat last year, it had a misfire and I switched coils to isolate the problem being the coil. I replaced it with a used one I got with the boat, and it fixed the issue.

The engine is a bit of a Frankenstein.... engine 125 and lower unit (with the serial number) is a 85hp. The engine has only been put on in the last few years by the previous owner.

Im going to put new connectors on the cylinder 4 wires, try that.

thanks

 

[Jiggz]

I have the same engine. The blue coils are the original ones for the '89-125. Part # is F684475. If it is any help, if you are not using the NGK BUHW or BUHX as spark plugs, I highly recommend you do. It'll idle and run a lot smoother with this spark plugs. As for the idle fuel air mixture screw, set it around 1 1/8 - 1 1/4 from slightly seated.

As for the lower unit being an 85 LU, that is because the original owner wants higher torque output by using a LU with higher gear ratio. The original 125 LU has a 1.73:1 ratio while the 85 has a 2:1 ratio.

 

[BackyardKrazy]

I just checked my plugs, they are the BUHX. And yes the lower unit has a lot of acceleration, I had to put a 21 pitch prop on it to get it to run at 5000rpms. I really like the engine, its got 150 psi in all cylinders, and with a boroscope I can still see the cross marks in the cylinder walls from honing. Maybe someone had it rebuilt.

 

[Jiggz]

Great.

 

[jerryjerry05]

The bore scope should show the top of the piston.
​If it's been rebuilt and the pistons replaced the new pistons will have a number stamped in the top.