Trying to Solve Poor Performance

Mako19Sam

Recruit
Joined
Jul 7, 2009
Messages
1
I have a 1973 Mako 19 with a 1996 115 HP 2-stroke, 4 cylinder Mercury. The boat is a bit heavy, but still rides with the scuppers about an inch out of the water (typical.) The engine is running well in terms of starting and idling, but it's a bit sluggish getting on a plain and tops out at about 22 mph @ 3200 RPM. The prop has been painted, but the last two digits are 19, so I assume I have a 19 pitch, 3-blade Quicksilver prop on. I don't know the ratio, but I am guessing 2.07. Any thoughts or recommendations on props or other things to check? Thanks!
 

countvlad

Chief Petty Officer
Joined
Jun 29, 2009
Messages
439
Re: Trying to Solve Poor Performance

I have a 1973 Mako 19 with a 1996 115 HP 2-stroke, 4 cylinder Mercury. The boat is a bit heavy, but still rides with the scuppers about an inch out of the water (typical.) The engine is running well in terms of starting and idling, but it's a bit sluggish getting on a plain and tops out at about 22 mph @ 3200 RPM. The prop has been painted, but the last two digits are 19, so I assume I have a 19 pitch, 3-blade Quicksilver prop on. I don't know the ratio, but I am guessing 2.07. Any thoughts or recommendations on props or other things to check? Thanks!

tops out meaning thats WOT or thats as much as you can get out of it(at half throttle u hit 3200rpms and you cant get nothing past that point).... if thats your WOT then ur overpropped... if thats as much as you can get out of it sounds like you might have to rebuild your carburators.... or you might have other issues

has the boat sitting for awhile? look on the forum and find the decarb technik using seafoam... i does wonders.. good luck
 

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: Trying to Solve Poor Performance

Sam, I show your motor should have maximum recommended RPM at 4,750 to 5,250 RPM with a 2.07 gear ratio and an allup weight of about 2,600 pounds. Please check this for me. Under these guidelines you should be turning a 19" pitch prop and doing about 36 MPH.
So the prop is not the problem, it is the motor. I would go to the Mercury outboard forum on Iboats and post that you have a motor problem and get some help from them.

H
 
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