No power under load

[HandyJack]

Have you had this engine since new? If not, do you have any service records from the past owners?

No, it's second-hand. I think the previous owner didn't believe in service records. My thinking was the same as yours. Probably a good time to change the pumps anyway.

[HandyJack]

Well guys, I replaced both pumps and he's still sluggish. No change at all. That concludes the entire fuel line. My next guess is maybe the coils or CDI? Does anyone know how to ohlm a coil to check if it's working? My spark plug tester says they're all firing.

[99yam40]

If you want to test the CDI and its inputs
this is a good guide if you do not have the Yamaha manual or your motor
View Troubleshooting Guide | CDI Electronics

[HandyJack]

If you want to test the CDI and its inputs
this is a good guide if you do not have the Yamaha manual or your motor
View Troubleshooting Guide | CDI Electronics

Thanks, I'll be testing it tonight after the kids get put to bed.

[ausnoelm]

You haven't cleaned the carbs yet!

[HandyJack]

You haven't cleaned the carbs yet!

Thanks Ausnoelm, but

Carbs are rebuilt back in April. No problems until just a few days ago. I'm stumped.

[ausnoelm]

Being done months ago doesn't mean they don't have dirt/crap in them now.

[HandyJack]

Well the cdi and coils are fine so maybe it is some fluke in the carbs? I'll tear into them today i guess. Ugh!

Someone said it might also be the neutral safety switch keeping the rpms at 2500.

[sony224422]

I had the same issues, ended up being dirt and crap in the carbs. I went through everything you're doing because i was told carbs were rebuilt before i bought it.

I'd pull them apart and clean them well, and blow air through all the passages and everything. Hopefully that will fix it for you.

[HandyJack]

Well i went through the carbs with a fine toothed comb and blew the crap out of them onto a set of white paper filters. Nothing came out and all the jets, tiny holes, and lines were clean.

I checked the oil tank on the engine too while i was at it and pulled a dadgum moth out of there the size of your pinky nail.

Whaaa?

So I pulled the main tank and checked it. That's a fun job. Nothing weird though and the inside is clean. Must have landed in there when i was replacing it last year. The PO broke the sensor off inside the tank. I had the cover off for a few days waiting on parts. Never did i think it would look good to a critter, LOL!

Anyway, I fired it up and took it around the lake. No change. It heads right up to about 2700 rpms and then drops back to 2500 and stays put.

I'm back to square one. Any other ideas? 2500 RPMs is the safety zone on this engine so I'm leaning toward something electrical myself. I just don't know what.