1985 force 125 cylinder firing problem

[Live4Water]

O.K. I really need some help...........

I bought a 1985 Four Winns off craigslist over the winter and have been nursing it to good health again, but now I am at a loss with this final problem

Here's the symptoms: Boat reaches top speed of 31 MPH ......when it wants to.
Randomly, it feels like 1 or 2 cylinders simply stop firing; instantly. Then instantly they will kick back in again.
There is no rhyme or reason to this, sometimes they cut out momentarily, sometimes (alot more lately) they won't come back on line at all.

Here's what's been done:
At first I thought it was an overfueling problem since plugs were coming out really fouled after use, so carbs were cleaned and completely rebuilt
Then I thought maybe timing was off, so a timing light was brought in and fly is exactly 30 degrees off TDC as it should be.
I then noticed the lower 2 cylinder plugs (3 and 4) were firing clean with slight carbon as would be expected, as well as cylinder 1 but 2 was only wet with fuel
This made me think CDI for numbers 1&2 was bad, so it was replaced.

I even completely emptied and cleaned tank and refilled with fresh mix!

I've got to start being more scientific with this and stop throwing parts at it.

I would really appreciate any direction that could be given from someone with greater knowledge than me!

Is there a way I can/should test each of the electrical components I.E. trigger, stator, coils, even the CDI's? I have a multimeter, I just don't know enough about the electrical on this engine to figure this out.

​Can someone help???!!! I just want to take the kids tubing like I promised them over the winter! Thanks

 

[Jiggz]

Even with great knowledge of these motors require a great deal of testing and troubleshooting to get an accurate diagnosis. In your case, you need to find out first if the problem is electrical or fuel related. Fuel related problems are easy to diagnose with correct tools and techniques. First, install a clear fuel filter between the fuel pump outlet and the carbs inlet. You can just use the cheapo G2 from w-mart for less than $5. When you experience the problem, check the clear fuel filter if it is full or at least 3/4 full. If it is then the problem could be electrical or it could be the carbs. Since there are two carbs, the likelihood of both carbs going bad at the same time is very unlikely. To isolate only each carb, use the fuel mix spray method of testing. While experiencing the problem, spray fuel mix directly into each carb. If the carb is working normally to start with before the fuel spray, it will stutter or try to bog down the engine decreasing the rpm due to high rich fuel going into the cylinders. However, if spraying fuel mix increases the engine rpm, then you can conclude that carb is not working properly and should clean and set properly.

If both carbs are found to be working normally, then the problem could be electrical. First, check there are sparks in each cylinder using an in-line spark tester. And then we can just go from there. Electrical troubleshooting are more complex and tricky. but spark testing is a very good start. Make sure also the carbs idle mixture screws are set properly at 1 turn out from slightly seated.

 

[jerryjerry05]

Dropping a cylinder or 2 could be either electrical or fuel.
Start with the basics.
Compression then a spark test.
Then check the fuel pump diaphragm for holes.
The boats an 1985 is the motor the same?
There is a site called Outboard ignition . com and CDI ignition .com both have test procedures for the ignition.
The 85/125 came with the plug and play connectors.(junk).
You can cut the connectors and hook them direct. If they are not making contact.
Post the test results.
Try cleaning the carbs and making sure there is no junk in the fuel system.
Add a filter between the pump and the carbs.(wallyworld G-2 or G-12)
While the carbs are off check the reeds behind the carb.