Is My Prop To Big

[spicerak]

I Have A 150 Evinrude With A 21 Or 23 Prop It Only Gets To About 4500 Rpms And About 30 Mph Is My Engine Working To Hard Should I Go Smaller Not Sure What To Do Thanks For The Help

 

[crb478]

Re: Is My Prop To Big

If your engine is running correctly and your boat is not waterlogged or too heavy for the engine then you are about 1000 rpm's on the low side and could probably benefit from dropping prop sizes. Depending on what kind of boat you have. See if you can borrow a 17 pitch prop from someone and how it performs.

 

[spicerak]

Re: Is My Prop To Big

What Do U Mean By Waterloged.if I Went To A 17 Would The Rpms Go Up I Have A 18 Ft Neptune Sunbird. If Anything Engine To Heavy For Boat.what Rpms Should I Be Running At Am I Using A Gas Hog Because Of It Being To Big Thanks.also I Scarde To Go To High On The Rpms.am I Woking The Engine To Hard With The Prop I Have

 

[haskindm]

Re: Is My Prop To Big

The correct prop will allow your engine to meet its rated maximum RPM at WOT (wide open throttle). Sometimes the foam flotation in a boat becomes waterlogged adding hundreds of pounds of weight and negatively effecting performance, so check on that. If that checks out OK and the engine is running correctly, you should go to a lower pitched prop to increase RPM's. Too much pitch causes your engine to "lug" increasing wear on the engine and using more fuel. There are many posts here about selecting the proper prop. Spend some time reading and it will begin to make sense.
Check your owners manual for proper WOT RPM. Most outboards are around 6000 RPM, but check to see the proper range for your engine.