1989 2.3L OMC Cobra RPM Question

[phaven]

I recently purchased a 1989 Four Winns with a 2.3L OMC (Ford) Cobra engine. This is my first I/O... Something that has bothered me since getting the boat, is that I don't seem to be able to "use" all that the engine has to offer.

The guy who sold it to me said I should treat 5500 RPM as the red line. Four Winns confirmed this. However, when I get up to planing speed, I have lots of engine left at 5500 RPM. I've confirmed that I have the standard propellor (17"), and am wondering if it is typical to have about 1/3 of the throttle left, or if there might be something else wrong. I feel like I should be able to just put the throttle down and give it everything...

Thanks in advance.

 

[marunr]

Re: 1989 2.3L OMC Cobra RPM Question

hmmm. I use a 15 prop on mine and the WOT is about 5200. I would think you would have trouble reaching 5500 with a 17 pitch prop. What size is your boat? I get 35 to 37 mph at WOT. I have to wonder if your tach is accurate.

 

[phaven]

Re: 1989 2.3L OMC Cobra RPM Question

I would love it if it were just the tach!... The boat is a 17' Four Winns 170 Freedom. I've only been able to get to about 28mph at 5500 RPM. But typically, it's more like 20 - 25 mph, especially with a couple people in the boat. I've never been WOT because it would bury the needle...

 

[Coors]

Re: 1989 2.3L OMC Cobra RPM Question

I think your speedometer is off, as well as your tach; the numbers don't jive

 

[marunr]

Re: 1989 2.3L OMC Cobra RPM Question

Yea, I think you need to verify the tach and speedo. My boat is 17' also, so I don't think you're truly at 5500. When I pull a skier at about 25 mph the rpm's are about 3500 to 3800.

 

[phaven]

Re: 1989 2.3L OMC Cobra RPM Question

Thanks for the advice - I'll get them checked out.