OMC/Cobra Help

Could use a bit of help here. Here's what I have It's a 1990 Renken 2000 Cuddy with a 2.3 OMC/Cobra. Now for all I can find on this my max. RPM range should be 52-5600 and all I can get is about 42-4300 at approx. 23-25 MPH. I just bought this boat and it's my first IO set up so I know next to nothing about it. Could I have a wildly incorrect prop or a lower gear set or what? I have no idea what prop is on it as I can find no markings on it so if anyone has any ideas as to what pitch range prop it should have and why my RPM's seem so far off I'm fairly mechanically inclined as far as if I need tuning/engine work and don't mind buying a new prop if I have to. If you need more info. let me know and I'll tell you all I can to get this thing fixed. It's a bit long for a first post but I would really appreciate any help I can get with this THANKS

Re: OMC/Cobra Help

Could it possibly be a bad fuel filter?

Re: OMC/Cobra Help

where are you getting those WOT numbers from
.It sounds like your in the recommended range now.

Re: OMC/Cobra Help

I have a 89 3ltr omc and wot for it is 4200 to 4600 rpm.Your #'s seem high for wot.I have a 17 pitch prop on mine(89 renken 21 ft)at 4600 rpm I'm at around 30 mph.Yours sound's fine.

Re: OMC/Cobra Help

SHIMANOFAN said:

I have no idea what prop is on it as I can find no markings on it

Click to expand...

The prop make and model should be molded into the hub, right around the prop nut.

Re: OMC/Cobra Help

Start by checking the basices, if you haven't already:

1. Download the OMC manual from the I/O Adults Only forum.
2. Warm the engine up and run a compression check.
3. Put new spark plugs in it with proper gap.
4. Check the plug wires for condition, corrosion, etc.
5. Check the distributor: cap rotor, ignition points (if so equipped).
6. Check the timing. (I have a 1987 2.3L Ford OMC and the timing was WAY low when I bought it. The engine really perked up with the correct timing.)
7. Check for old gasoline. Replace with fresh.
8. Check for fuel delivery from the tank to the carb: bad check valve, bad fuel hose, trash in the tank, etc.
9. Check the outdrive for proper oil level.

These are just things I did to my 2.3L. I'm no marine engine expert, but they did help.

Re: OMC/Cobra Help

I've been corrected and my RPM Range is correct. I've done all the other stuff but checked the timing. The prop is a 14" dia.x17" pitch. Everything seems to be as it should so I'm wondering what I can do to raise my top end maybe a 19" pitch prop. I'm not worried about "Hole Shot" power I'd just like to increase my top end a bit.

Re: OMC/Cobra Help

I amagine a 19 would increase your top end,not sure how much though.There is a prop forum, you may get more answers there.