1991 phaser motor prob.

[Motorhead]

Having an issue with this phaser. It idles and runs nice up to say 1/4 - 1/2 throttle, but seems a bit fat. Once you try more for speed it really seems rich and bogs, let up and it runs ok on 2 cylinders and again idles great!
Thought for sure it was carb probs so I cleaned carbs twice with no change. Bought a used pair of carbs, cleaned those and tried them same prob. Did check reeds and they look good, compression at 126 on both without touching throttle during. 1 side plug looks brownish, other black/grey and wet. Took the exhaust off and shook it around, pretty light and nothing loose inside! Shall try burning the exhaust to make sure no nests inside I guess.
Would stator coils act that way? Whereas it idles so good and runs on low end can I rule out seals?

 

[yamahamark]

Could possibly have a bad seal or gasket. Start it and spray it with staring fluid.

 

[Motorhead]

I will buy a can of ether and give that a try.

 

[Extreme Elmo]

when it bogs give it some choke and see what happens, if it revs up your lean

 

[Trailman]

The rubber plugs in the carbs can be put in the wrong holes, parts diagram from Yamaha even has them shown in wrong location.

 

[Motorhead]

Thanks for all the good suggestions. Found the issue, primary clutch was sticking. Never thought it was the primary whereas it engaged at normal rpms. Had tried different settings on secondary but was still bogging, man checked everything and thought what the heck let's take off the primary and clean and inspect! Even when I found it to be sticky, I was not sold on my finding the problem because in the past sticky primary clutches always acted different with increased revs and not shifting out. While I had the clutch off I did the ether check on all seals and gaskets with no rev increase, but I did notice that the engine sounded nice and revved up to 6 - 7K without any bog with just a quick blip of the throttle. So yeah, put the clutch back on and there she is hooray!! Did some secondary clutch re- tweaking and ended up at C3.
Have had many phasers 1and 2 and forgot how much fun this sled is on small trails, wow! I had gone through the whole sled, needed a front shock and the rear suspension was also rusty and semi seized, Did I say how much fun this light sled is!! Thanks again for the quick responses all. Great site huh, second to none..