Timing plate adjustment on Yamaha 130hp

[shrkbait]

Hi - I have twin 1993 Yamaha 130TXRR motors - 2 strokes. They have served me well the 7 years I have owned them, but have become a difficult to start, and seem to have lost a little of their power at WOT...

So, I set about to try to check all the periodic service settings in the Yamaha shop manual. However, in looking at the timing plate adjustment, the manual states to use a dial gauge in cyl 1 and turn flywheel clockwise to find TDC, then go toward BTDC 3.05mm (I am going counter clockwise here, is that right?), then set the timing plate to 22 degrees. But the plate has limited adjustment, and i'm in the 8-11 range... So I checked the second engine and got the same result. So - I don't know too much about these engines, but assume they would not run properly (if at all) if they were that far out. And the chances of them both being off, by almost exactly the same amount, seem very small, so... Am I misunderstanding the procedure and doing something wrong, or what's could be up here? Thanks!

 

[shrkbait]

Re: Timing plate adjustment on Yamaha 130hp

rrf

 

[99yam40]

Re: Timing plate adjustment on Yamaha 130hp

Have you checked the timing with a timing light to see if it is in spec at idle and WOT instead of trying to reset?

How about the compression and spark
Fuel pressures would be good one to test also

 

[shrkbait]

Re: Timing plate adjustment on Yamaha 130hp

Have you checked the timing with a timing light to see if it is in spec at idle and WOT instead of trying to reset?

Perhaps this is a stupid question, given my ignorance of engine mechanics, but if the basic timing plate reading is off, won't that throw off all the other timing readings done when the engine is running?

 

[robert graham]

Re: Timing plate adjustment on Yamaha 130hp

Hi - I have twin 1993 Yamaha 130TXRR motors - 2 strokes. They have served me well the 7 years I have owned them, but have become a difficult to start, and seem to have lost a little of their power at WOT...

So, I set about to try to check all the periodic service settings in the Yamaha shop manual. However, in looking at the timing plate adjustment, the manual states to use a dial gauge in cyl 1 and turn flywheel clockwise to find TDC, then go toward BTDC 3.05mm (I am going counter clockwise here, is that right?), then set the timing plate to 22 degrees. But the plate has limited adjustment, and i'm in the 8-11 range... So I checked the second engine and got the same result. So - I don't know too much about these engines, but assume they would not run properly (if at all) if they were that far out. And the chances of them both being off, by almost exactly the same amount, seem very small, so... Am I misunderstanding the procedure and doing something wrong, or what's could be up here? Thanks!

I really believe you may have some starting/performance issues other than timing. Maybe have some weak cylinders, carbon, stuck rings, low compression, dirty carbs. Check compression on all cylinders, have carbs cleaned and set, do a de-carb on both motors, check/clean/replace all fuel filters/screens. Good Luck!

 

[99yam40]

Re: Timing plate adjustment on Yamaha 130hp

If you are speaking of making sure the timing marks are at the proper place, I always thought that with #1 piston at TDC the timing mark should be lined up there also on all motors.
But I do not know anything about your motors either or your manual so take that as an opinion.