1976 Mercruiser 233 RPM and Prop questions

[Lancer76]

A new to me Chris Craft Lancer 23 with a MERCRUISER 233. I spent the summer chasing down a cooling issue and replacing a variety of engine and outdrive parts (maintenance things). Fixed the overheat issue and it ran great - just in time to winterize and put away : ( . However, the boat ran up to 5200 RPM at WOT, which seems high (44 mph). Turning a 15 x 17p aluminum 3 blade prop.

Two things
1. What is the recommended high-end RPM for this 41 year old engine?

2. What prop would you suggest for this set up?

Thank you.

 

[alldodge]

The 233 WOT RPM is 3800 - 4200
Timing 10 BTDC

Showing 5200 I think your tach is defective

 

[Lancer76]

RE: Defective Tachometer - that is possible. It's original equipment. I've double checked the lower end with a digital tach and it was pretty close. Have not verified high end of RPM range.

Thanks.

 

[tango13]

My 1977 250 mercruiser (350 chevy) can turn 5000+ no problem with a 15 x 17p, prop. I would think that 5200 would be a pretty normal WOT for 4bbl Ford V8

 

[Bondo]

My 1977 250 mercruiser (350 chevy) can turn 5000+ no problem with a 15 x 17p, prop. I would think that 5200 would be a pretty normal WOT for 4bbl Ford V8

Ayuh,.... Yer motor is recommended to run 4400/ 4800 rpms at Wot,....

Ya need a 19" prop,....

 

[alldodge]

Yer motor is recommended to run 4400/ 4800 rpms at Wot,....

Agree

can turn 5000+ ........ . I would think that 5200

and if this is turn your tach needs to be checked for accuracy or your going to be buying another motor soon

 

[Lancer76]

Thank you for the information. Being in Maine, the boat won't turn over 0 RPM until spring so the engine is safe for now. Come spring I will verify that the tach is true (or not) and reprop accordingly. In the meanwhile, I'll boat vicariously through those in warmer climes and plan my boat shed for the 2018/19 winter. Tired of shrink wrapping and the very limited access it allows.