What size prop for my 200 EFI merc

[mkeleher]

Need some help figuring out the correct prop size for my motor. I have a 1991 19 ft norris craft FISH AND SKI that has a 200 merc on the back. It used to be carburated then was changed over to EFI. It currently has a 25p tempest plus but from what I have heard this prop is too big for the motor( so my brother says). I cant get the motor over 4000 RPM's with this 25p and it is VERY sluggish out of the hole. Top speed is around 50 mph trimmed out. If I go down to a SS 21P 3 blade will that get me where I need to be or is this the correct prop and the motor isnt running correctly? Thanks in advance for the help.

 

[brianspot]

Re: What size prop for my 200 EFI merc

If you use a 21" or a 19" you will be much more satisfied. It's like night and day. And you will love how it handles. You brother is right about being over proped. You should be running your engine around 4400-4800rpm. Otherwise you can do major damage to your engine. Switching to one of these smaller pitch props will fix that for you. Just make sure you know what your rpm specs are needed lo be with your specific model boat motor and stay with in those specs. You will extend the life of your motor and have much more fun as well.

 

[mkeleher]

Re: What size prop for my 200 EFI merc

updating,

I called the manufacturer of Norris craft today to get the exact answer. Unfortunetly for me the 25pitch is correct and the motor is not running right. a 19ft norris craft fish and ski with a 200 merc should be in the 70 mph range and run a 25 pitch per the manufacturer. Maybe my throttle is not allowing the motor to open up all the way? Anyways, off the the mechanic it goes I suppose. CHA CHING$$$$

 

[allen russell]

i just removed a 21-pitch high five on my 200 2.5 efi merc on a 18.5-foot ranger it was turning over 6000 almost 6300 to many rpms but will blast out of the hole wow i mean blast running in the mid 70ts so i went to a 23-pitch high five 5 blade i just love the way these props blast you out of the hole have not been back to the lake yet with the 23 pitch i will keep you posted

 

[QBhoy]

Re: What size prop for my 200 EFI merc

If you use a 21" or a 19" you will be much more satisfied. It's like night and day. And you will love how it handles. You brother is right about being over proped. You should be running your engine around 4400-4800rpm. Otherwise you can do major damage to your engine. Switching to one of these smaller pitch props will fix that for you. Just make sure you know what your rpm specs are needed lo be with your specific model boat motor and stay with in those specs. You will extend the life of your motor and have much more fun as well.

This is just wrong, in all aspects, I’m afraid.

 

[QBhoy]

Something isn’t right to me here. Even if a 25” is deemed to be a little over pitched (tempest plus can act like an inch more than they are in my experience)…you’d imagine it’s not too far off. So if you were to go to a 23”…you’d still in theory be way way off with the rpms.
I’d think something else isn’t right here. Time to check the engine over I think. You should be easy running a 23” very happily with that set up. Wonder around the conversion on the engine you mention too. Certain your issue isn’t the prop. You won’t be far off the mark for pitch. But you’re way off the mark for revs for sure. That far off that it suggests it’s not the prop that’s the issue

 

[flyingscott]

Something is drastically wrong there. I would start by looking at the EFI conversion.