yamaha 150 dropping rpms

[fphillips]

Bought a new Parker in Jan. 07 equipped with 150 4-stroke. Now has about thirty hours on it and it has had its 10h service by dealer. Trailered it down to Fla. this month and had a few occasions while running at 3800-4000 rpms that the rpms suddenly dropped. Engine never quit and the rpms quickly rebounded. Fuel tank still has about 40-50 gallons of original fuel supplied to me by dealer in Jan.. Fuel filter in engine shows no sign of water and have changed in line 10 micron filter again with no sign of water. However, engine continued to occasionally drop rpms. Any thoughts or suggestions?
Thanks,
Frank

 

[blued]

I have the same motor. About the same hrs on it
My motor will stall sometimes when I put it into gear. (This sucked when docking and reverse failed)
My dealer tells me other people "3 or 4 guys" are having the same problem and Yamaha is not getting back to him with any support. So now I have to wait until they get back to him.

Dropping RPM or stalling is a problem.

I just filled out my customer survey with some "dissatisfied" check boxes.

 

[Lucky John]

Mine also stalls out once in awhile when putting it in gear,the second or third time I was docking it stalled with 30+ knot wind,thankfully I made a quick recovery.Do you guys get a pinging sound @ 4800 rpm?I get it when I'm at 47-4900.Some things will have to be addressed at the end of this season. :?

 

[blued]

I don't seem to have any PINGING, but I will be listening a little better this weekend.

 

[Don't Trip]

Check your ground connections all the way back to the one on the block, I had some simalar symptoms, and it ended up being a bad ground/cable to one of the motors(twin f150's). The connection on the block had some minor burning discoloration like it had been arcing intermitantly.

hope this helps, spent about 13 months chasing an electrical ghost, new cable and the rig has never ran better, even starts faster.

out

 

[Wild Bill]

It would not be something as simple as the throttle tension would it? I run my bud's new F150 and had to set the tension up or the throttle would slip back. You said it recovered. If it did this on its own without touching the throttle, then it is something else.

On my bud's motor the selling dealer just put the motor on, put oil in it, hooked up the batteries and started it with a hose attachment. There are codes that the dealer is supposed to check or set as dealer prep. This was not done and the motor bogged down when put in gear and given fuel. Since another certified Yammy mechanic set it up properly, it has run fine.