Rebuilt motor with problems

[victorc1]

Need some help, I rebuilt my 1996 Mercruiser 3.0 LX motor, mounted it on my Monterrey 180 SCR, when I run the boat I have 2 problems.
1. I can't get the rpm's to go past 2000 on WOT and top speed is 30 MPH.
2. Oil comes up through the tube that connects from the valve cover to the carburator.

 

[Don S]

Re: Rebuilt motor with problems

1. I can't get the rpm's to go past 2000 on WOT and top speed is 30 MPH.

Either your tachometer is wrong or your speedometer is. No way is that boat going to go 30 mph at 2000 rpm.

2. Oil comes up through the tube that connects from the valve cover to the carburator.

How much oil? is it milky? Is the oil level way over full?

 

[Northernbob]

Re: Rebuilt motor with problems

Sounds like too much blowby?? Oil level to high, foaming??
Should do a compression and leakdown test. IMHO

 

[victorc1]

Re: Rebuilt motor with problems

Okay I checked the RPM gauge it was set for at 8 cylinder, changed it to 4 cylinder, now the RPM's are marking correctly and I had added too much oil. So everything is running correctly.
Is top speed for this motor 30mph at 4000 rpm's?

 

[ENSIGN]

Re: Rebuilt motor with problems

I would check my speed with a GPS,How fast is going to depend largely on the weight of the boat and how you operate it.How much crap you got onboard,is the bottom clean,Are you using the trim properly???