Cold WOT rpm loss,2500-3000 warm 5000

[piper8150]

I am running a 1987 115hp ETXH. It will not go over 3000rpm at the start up but after running 15 min or so at reduced rpm it kicks in and is ok rest of the day. Same thing next day, also I think it is misfiring. I have checked the thermostats and temperature sensors and they are ok according to Seloc. I have rebuilt the carbs twice and sync the timing according to Seloc, I've had the engine 6 years and this started about 2 years ago and seems to be getting worse. I don't know what to next. Thanks for any help you fellows can offer.

[99yam40]

did you even check or replace the fuel pumps?

[piper8150]

yes the fuel pump, fuel, fuel lines and ball were replaced

[99yam40]

I would look at spark and timing while the problem shows up to see if they are different that when running well

[piper8150]

Thanks I will do that in the next few days

[piper8150]

As it turns out, the misfire led me to find no 2 was not firing, that led me to check the CDI that turned out to be bad, changed that and the motor runs great. All this time I was chasing carb and gas, never thought a CDI could act like that. Thanks for all the help

[99yam40]

yea, testing inputs and out puts to CDI will/ should tell you a lot while troubleshooting and save a lot of time.

Good to hear you got it running well agin.



are you sure it was not just a bad connection to a pulser coil that got better when unplugging and reconnecting the CDIs

But then I do not if #2 has it's own pulser so I may be way off base

[piper8150]

I tested the CDI on the motor and of the motor with the same result . the continuity of all the wiring was also checked and was found to be good. Your idea to check the sinc was the thing that really led to the discovery of the faulty CDI. I'm grateful for all the help. I'm retired and have limited income so I have to fix things myself, this forum is a great help to everybody, Thanks again