Yamaha VMAX 150 - 2001 - Power loss

[wschwarz2010]

Last year the engine was great. 5500 rpms and 60 mph. Great prop from Ace Props in Canada. Got it in the water yesterday started off with 5400 rpms and 50 mph and idle arround for a while. My five year old was steering for a bit. Then could not get on plan at all really. Finally did and got to 4000 rpms and 35 mph. WHAT? Put the boat in neutral and could have pushed it to 5500+ rpms easy. Could this be the gas from last year?

 

[Captain Paul]

Re: Yamaha VMAX 150 - 2001 - Power loss

I also own that motor,OX66 version. 100 RPM's is NOT going to equal ten MPH. Was that on GPS? I do not beleive these motors like to be run at high RPM's in neutral. I never run old gas. Other than lower RPM's, how did it sound while running?

 

[wschwarz2010]

Re: Yamaha VMAX 150 - 2001 - Power loss

Sounded alright. No sputtering or coughing. Just last years gas. I will draining what I have and replacing the water seperator to start. Fuel pumps are new last year as well. Thanks for the reply - any thoughts?

 

[rodbolt]

Re: Yamaha VMAX 150 - 2001 - Power loss

last year it did not have nasty gas.
you need to test compression,test spark.is this V150 or a VZ150 or a VX150.
all 3 used very different fuel and ign systems.
all said Vmax on the cowl.

 

[wschwarz2010]

Re: Yamaha VMAX 150 - 2001 - Power loss

Question: Is this V150 or a VZ150 or a VX150. It's a V150-TLRZ.

Last year I had work done on it and the gas I put in after was from a highly active station. Bad gas and other things cause me to have a new piston installed, the engine was rebuilt, fuel pumps changed, water seperator installed.

Infact the last weekend I ran it it was doing greating 58-60mph. Ran like a champ.

The gas was treated with Marine Stable and should be OK, but it will all go now.