Prop selection

[firstimeboater]

I have a mercruiser with a 350 5.7L with 210 HP. I bought the boat used and its not getting me out of the hole. My top RPM is around 3500 with a 14" x 19pitch prop. Does anyone know what size I should be using. My operating range for RPM by the book is 4200-4600 rpm.

 

[Perfidiajoe]

Re: Prop selection

I believe you have too much pitch, 15 would be much better. I thought a 5.7 had more H.P. than 210. We don't know what kind of boat your pushing around, would be helpful in finding a solution. Most of the time 1" of pitch lower is worth about 200 more RPM's Joe

 

[firstimeboater]

Re: Prop selection

I have a 19' sea ray 1996 open bow. They make a 210 and 250. I'm not sure what hp I have so I say the smaller one cause I can't turn a 19pitch prop. Am i right in that?

 

[Perfidiajoe]

Re: Prop selection

Is the engine up to specs., compression, timing, carb., WOT setting, ignition including plugs & wires, etc. If all is ok, try a lower pitch prop. See if you can borrow one to try out, before buying, you want to be when lightly loaded, near the top of the RPM range for your engine. If not up to specs. do the repairs, or adjustments first, then retry. I would think w/ a 19' boat, & 210 HP you should turn a 19 pitch prop faster than 3500. Good Luck, Joe

 

[Coolmaker]

Re: Prop selection

The rpm range for that motor is 4600. It sounds like you have a problem with ( plugs, timing, carb, fuel pump, fuel filter). That engine, in that boat should have no problem turning a 19" prop.

 

[Coolmaker]

Re: Prop selection

The rpm range for that motor is 4600. It sounds like you have a problem with ( plugs, timing, carb, fuel pump, fuel filter). That engine, in that boat should have no problem turning a 19" prop. If the engine is okay...

 

[firstimeboater]

Re: Prop selection

The guy worked on my boat says that the engine maybe a car engine. He's not sure. What hp would I have if it is a car engine and how would you know If it was a car engine? 8cylinder GM