OMC Cobra TKO4 not reaching Ideal RPM's at full throttle.

[stylze76]

I have an 89 sunbird corsica 175 with an OMC Cobra TKO4 128hp 2.3L engine that isn't reaching the ideal rpms at full throttle. Ideal per the manual is 5200-5600 and i barely hit 4500. The boat and trailer together weight 2960. The prop is a Piranha 13.25 x 17. Can anyone lend some wisdom on why this might be or what I could try. I also have another prop that is an alluminum prop of that same size, not sure that would make a difference.

 

[enginerd]

Re: OMC Cobra TKO4 not reaching Ideal RPM's at full throttle.

Hi,

Do you have any history with this boat? Do you know if it ever reached 5200+ with these props? If so, a tuneup might help. Does it have fresh gas? You could try a smaller pitch prop too. Point #2 on this page should help: How to Choose a Boat Prop, iboats.com How To Library

I would urge you to make sure the engine is running good before investing in a prop. Someone who owns a similar boat with this drive might be able to help too.

Eric