1993 Yamaha 200 hp txrr carburated

[yamatwin]

1993 Yamaha 200 hp txrr carburated. Twin 200's mounted on Mako 261B. Normal rotation motor will not rev to max rpm. Runs almost smoothly thru 4200rpm. Sputters (kinda) and will not reach max rpm usually for that motor 5400. Cleaned carbs and replaced fuel pumps. Ball is firm while trying to reach max rpm. Disassembled and spayed carb cleaner thought out carbs and ran engine at full throttle nice plumes from all six barrells. Pulled manual choke and engine bogged down. Sprayed extra fuel in carbs and that did not help. Fuel flow looked equal and plentiful. New fuel pumps. Compression is good. Swapped CDI units between engines did not help. Electrically checked Ignition coils, stator and pulsor coil all checked to the manual specs. Could they still be bad?

 

[DJ]

Re: 1993 Yamaha 200 hp txrr carburated

yamatwin,<br /><br />Do you have access to an inductive timing light?<br /><br />If so, put the inductive pick up on each plug and see if one breaks down.

 

[yamatwin]

Re: 1993 Yamaha 200 hp txrr carburated

how would it break down at high rpm or just at idle by attaching the light. Have checked each one with a light at idle and there seemed to be no change.

 

[JB]

Re: 1993 Yamaha 200 hp txrr carburated

Howdy, Yamatwin.<br /><br />You seem to have made every effort to prove that your ignition is okay on all 6 and that all six are getting fuel and have compression. I assume that your findings are accurate and that you have verified 100% throttle opening.<br /><br />As I see it, that leaves two possibilities: Scavenging and timing.<br /><br />Verify that the ignition timing is advancing with the throttle on the R engine just as it is with the L engine.<br /><br />Finally, your drop in max rpm suggests that only 5 cylinders are making full power. Disable each spark plug, in turn, while running. Do this under load if possible. If this is your trouble I expect that 5 will cause a drop in rpm and one, a dead one, wont.<br /><br />Check reed sealing in the dead cylinder.<br /><br />Let us know what you find.

 

[Salty Dog]

Re: 1993 Yamaha 200 hp txrr carburated

Did you do a compression test?