Need WOT RPM, and recommended pitch prop for 1969 160 mercruiser in formula 233

[rpeter46]

Hello,
I have a 1969 Formula 233 with a single 160hp inline 6. I can't seem to bring it above 2900 RPM. Before I start blaming my tach or ignition, or something else-can someone tell me how to find what RPM I should be running at WOT? Also, what prop should I be using? Thanks.

Paul

 

[Don S]

Re: Need WOT RPM, and recommended pitch prop for 1969 160 mercruiser in formula 233

3900 to 4300 is the WOT for your engine. If you are only getting 2900 rpm, you don't have a prop problem, you can't make up 1000 to 1200 rpm in prop pitch. You have something else wrong.
Here is a link to download the OEM service manual for your engine, you are going to need it. http://www.4shared.com/document/ozc1_97A/Service_Manual_01.html

Then, here is a list of things that can cause low WOT rpms. Check each item off the list as you confirm that it's Ok, and by the time you are done, it will run fine.
http://forums.iboats.com/showthread.php?t=295070