89 150hp Yamaha reving it up...

Asainz320

Petty Officer 2nd Class
Joined
Sep 27, 2006
Messages
137
When im running my 1989 150hp yamaha in neutral, i give a quick push and back to idle to the control arm to rev it up. It gets to around 4000 RMP prety fast, but it takes around 3 to 5 seconds to come back down after the control arm is back to its idle position again.

What does this mean? Is this normal in yamaha engines? or do i have dirty carbs?

Thanks
 

drewmitch44

Lieutenant Commander
Joined
Jun 26, 2005
Messages
1,749
Re: 89 150hp Yamaha reving it up...

im not sure since i would most likely not rev my motor up that high in neutral position. It might not be that bad to do it real quick in the water but i hope you are not doing this on the muffs. I have never done that. Just curious, but why would you have a need to do this? When you are in neutral you dont need that manny rpm's. I usually only go to 1500 max if im in neutral. I will not rev my motor over 1500 in neutral. I thought it was bad for the motor but i could be wrong.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: 89 150hp Yamaha reving it up...

Amen -- a two stroke engine can experience "run away" when reved real high with no load. You are unable to control it and it simply keeps reving until all the internal pieces try to get out of the crankcase. Don't do that anymore and you won't have to worry about it.
 

drewmitch44

Lieutenant Commander
Joined
Jun 26, 2005
Messages
1,749
Re: 89 150hp Yamaha reving it up...

I thought so Silver. There is no need to do this! It most certanly wont tell you if you need to rebuild your carbs! I think that the motor will now down rev cause there is no pressure to take the rpm's down. He said it would take a bit for the rpm's to come down, well i guess it would!
 

Asainz320

Petty Officer 2nd Class
Joined
Sep 27, 2006
Messages
137
Re: 89 150hp Yamaha reving it up...

I dont do it often, it was just the other day when i took it out. I know it is not good for any engine to rev up with no load, this is specially true for 2-stroke engines.
I guess yamaha is not the same as mercury when it comes to reving up when free of load.
 

drewmitch44

Lieutenant Commander
Joined
Jun 26, 2005
Messages
1,749
Re: 89 150hp Yamaha reving it up...

Its not good to rev up a merc when free of load even more! A merc will throw bearings really fast like that! Merc's are verry verry finickey like that!!! its is not so much a brand thing but more so than a type thing. They are 2 strokes! and even a 4 stroke i wouldent do that too.
 
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