force 1988 125 missing, sluggish

[Den68]

Hello all, just pulled my carbs and cleaned, checked the reeds, they were great. Put new plugs and cleaned up the wires, dog bone reeds and tubes good. When pulled the plugs all were lightly carbon up except for #2 plug was clean, so I figured that was the one giving me the problems. Took her out today and ran great and smooth for about 3 to 5 minutes and started missing again. pulled the wires of and it ran smooth without #1 top, so I'm wondering if anyone has had similar experience as this. I sure its not fuel now and am leaning toward the coil, going to order one tomorrow. When I got home I checked all wiring and its good no breaks or wear, so since it doesn't act up until its warm its got to be electrical, hopefully not the cdi box which would effect 2 cyl and hopefully not the trigger. any info would be great thanks

 

[jerryjerry05]

Start with a compression and a spark test.
outboard ignition . com has test procedures for your motor.
With an analog meter you can do most of the tests and figure out where the problem is??

I've only seen 1 bad coil in 30 years so don't buy until your sure.

I had that problem and it was the trigger.
The wires on the trigger are very thin and under the shrink wrap the wire had broken.
I changed ALL the connectors and the problem went away.

The pack has 2 circuits one can go bad.
Do the tests and figure it out.
Lots of good parts still available.

Not sure but they might sell some here?
If not e-bay is good.
It's like buying from the local store.
No cheats on ebay if you pay with Paypal.

 

[Den68]

compression good #1 140,#2 145, #3 150,#4 145 done with plugs out, tested all the wires, everything came back to specs on coils, stator and trigger, even wiggled the wires a bit to see if there was a possible break no problems, ran the motor with timing light, couldn't see any misses in spark. engine ran fairly smooth but really need to take it out and put a load on it, I'm doubtfull though. only thing I haven't done is change the fuel pump diaphragm, still waiting for that. Getting pretty confused and running out of ideas, but ill get back to you guys after I take her out again.

spa

 

[Jiggz]

Before you do more diagnosing, install a clear fuel filter between the fuel pump outlet and the carbs inlets. Thereafter, while doing the test runs, as soon as the problem arises, remove the top engine cowl so you can monitor the clear fuel filter. It should at least stay 1/2 ~3/4 full while running at WOT. If not then there is a fuel delivery problem. If it stays full then there is probably 1) carburetion problem, 2) Reed problem, 3) electrical problem. To do a quick check of the electrical problem, do the plug wire pull diagnosis while listening to changes in engine rpm. Note which plug does not affect rpm. Re-post your findings.