slow take-off for a 3.0 OMC

[dawson515]

I have a 1990 3.0 OMC Motor in my boat and it take a while for the boat to get up to full speed. It is a ski boat and there is no way that it can pull anyone out of the water. The boat tops off around 25 MPH and I know it should go faster than that. There is also water leaking in at the intake manifold, would this cause the problem? THANKS

 

[Bondo]

Re: slow take-off for a 3.0 OMC

There is also water leaking in at the intake manifold, would this cause the problem?

Ayuh,... While it may not be The problem,... It IS a Problem...

How long has it been since the motor was Tuned Up,..??
How long has it been since the drive was serviced,+ inspected,..??
How about a Compression Test on the motor,..??
What kind a rpms is the motor spinning,..??

You Might have a Sick motor, or possibly too large a prop on it...

 

[Don S]

Re: slow take-off for a 3.0 OMC

Or a prop beat half to death.

Here is a list of possible causes for low wide open throttle rpm.

http://forums.iboats.com/showthread.php?t=295070

 

[Lodgepole]

Re: slow take-off for a 3.0 OMC

Could be an exhaust flapper rotted/burned off and caught somewhere in the exhaust as well as any of the above.

 

[dawson515]

Re: slow take-off for a 3.0 OMC

A few replies to your comments:

1. It has probably been a while since there has been a tune up. I was given the boat last week, so I am not exactly sure.

2. I am not sure about the exhaust flapper.

3. The prop is in excellent shape.

4. The motor is running at a little over 2,000 RPMs wide open.

 

[Don S]

Re: slow take-off for a 3.0 OMC

4. The motor is running at a little over 2,000 RPMs wide open.

That's about half of what you should have, 4200 to 4600 is where you should be. Better start going through that list I posted.

 

[dawson515]

Re: slow take-off for a 3.0 OMC

Thanks for the list, I did read it before posting. Also the boat will not idle, you have to alway have the throttle down for the boat to stay running. And it could be a series of problems.

 

[dawson515]

Re: slow take-off for a 3.0 OMC

Thanks for the replies. I have the boat in the shop right now, so I will let you all know what exactly the problems were for those who have similar problems. Thanks