150 vmax 4800rpm max??

[jamesg]

I have a 200 150 vmax trly , recently rebuit with about 40 hrs on it.Yamaha says that this motor may reach 6000 rpm,but i have never gotten it over 5200.When i first got it ( i bought it 6 months ago from a guy that rebuilds them and sells them) it had a 14.25 x 22 prop.I would get47mph @ 5200rpm. Now i have changed the prop ( now 15x19 ) and have added a hydrafoil.Now it maxs out @4800rpm @40mph.The boat is a 19' bay boat and the 150 should be more than enough motor.Also i have had alot of problems with water in the gas , could that have something to do with the max rpm , even when the motor is running smooth.Any info will be greatly appreciated.

 

[rodbolt]

Re: 150 vmax 4800rpm max??

only one thing to do.
use test wheel YB 1626 and spin it up, if it wont turn the test wheel to at least 4800 its broke, if it will you have a hull/prop problem. post the entire model number as the V200 was made in serveral models in that year range.

 

[jamesg]

Re: 150 vmax 4800rpm max??

Sorry about the typo, its a year model 2000 150 vmax Trly, carb.

Could you please explain more about the wheel , im not much of a mechanic.

 

[jamesg]

Re: 150 vmax 4800rpm max??

Im also going to go out today and try the old prop.
Ill let you know what happens.

 

[DMSOUTH]

Re: 150 vmax 4800rpm max??

Rodbolt's right(as usual )-buy a test wheel or find a mechanic that has one and actually knows how to use it. That will tell you whether it's the motor or boat or hull. If you want to go hopin' and pokin', I'd change the prop to something like a 14.25 x 17--you're using an awfully big wheel for a small hull right now......

 

[Captain Paul]

Re: 150 vmax 4800rpm max??

Right oh!

22 is a bit-o-pitch. I run a 21 and can do 5500 with a light load, which the book say's is rpm max. I've read the rev limiter kicks out at 6000. a 19 should let you actually over rev. Are you sure the hydrafoil is not the problem? I know one owner whose boat would not get on plane very well, he took off the hydro and now it gives him whiplash.

 

[jamesg]

Re: 150 vmax 4800rpm max??

THIS IS WHAT HAPPENED TODAY
I put the boat in the lake with the 19 pitch prop, go out and open up to wot , now only 4500rpm and 38 mph
So im thinking i dropped a cylinder ( motor has recently been rebuilt)
I then went in and put the 22 pitch prop on.
Go out and holy s#$% ,now 5300rpm and 44mph
I ran around a while and was starting to feel pretty good about it , then the motor just shuts off when ildling.
Go back to wot and now only 4700rpm.
I get home and check the fuel water seperator and sure enough full of water.
I have had a constant problem with water , i just didnt figure that it would run smooth , but with lower rpm from water in the fuel.
What do you guys think??

 

[jamesg]

Re: 150 vmax 4800rpm max??

Ps , without the hydrafoil it porposis like crazy, taking it off is not much of an option.

 

[Captain Paul]

Re: 150 vmax 4800rpm max??

I would say first things first. Drain your fuel, check fuel lines and connections. Are you using e-10 fuel? If so, you cant have gallons and gallons sitting in the tank for months on end. You will take on too much moisture. How big is your tank? . I'm not the expert, but I would concentrate on your fuel/water issue before anything else. My experience with e-10 fuel is that it works great if you keep it fresh and don't store it for long periods of time. I have never had a problem following those guidlines.

 

[jamesg]

Re: 150 vmax 4800rpm max??

Yes , i do use the e-10 fuel, its all i can get where i live.
Its very confusing ,some people say keep your tank full,others say dont let the gas sit.
I use it once a week just about all year ( i live in florida)
and i was keeping it full.After abvout 6 trips i had to have the carbs done because of water. After that i ran all the gas out and i am dumping the fuel water seperator after each trip.
Sometimes she runs good , sometimes ruff.
But at least i havent had to have a carb job again.
Im going to try the electric fuel pump and copper line trick to try and completly drain the tank.
After that i will know how much is condensating and how much was already in there.

 

[Captain Paul]

Re: 150 vmax 4800rpm max??

Is the boat on the water all the time or on a trailer? I drain my fuel by disconnecting the line after the primer bulb, then I add a short line on the bulb, start priming it and let it drain into 6 gallon cans. A bit tougher when it's in the water I suppose. Since my system is vented, I like to add gas only as I need it, and only put in what I think I need. I only have a 27 gallon tank, so I realize we may be talking a difference in scale here.