1994 Bayliner 1850 Prop

[baylinerbud2009]

Hey everyone,
New to the boards and I have a prop question. My 18' Bayliner 4.3 merc currently has a prop that says 1423. When we are cruising my RPM's are very high, in the 5000's with still about half the throttle left to give. On windy days the RPM's stay down and I am thinking this is because more water is making its way through the prop area. Would increasing my prop size help to lower those RPM's? We would like to run with more of the throttle open. Thanks in advance!

 

[cooter2506]

Re: 1994 Bayliner 1850 Prop

First thing I would do is verify your tach with a shop tach. 1/2 throttle and at 5000 seems to be very high. If you check it and it is correct then change props. you have a 14 inch with a 23 pitch now. Every one in ch is pitch is about 200 rpm. Since you are high in rpms you need to move up in pitch. BUT I would verify that tach first. Was tach changerd lately. You could look on the back of the tach and see if it is set to the proper setting. It is a small potentiometer that will say 4, 6 or 8. That states number of cylinders.

 

[baylinerbud2009]

Re: 1994 Bayliner 1850 Prop

I checked the tach and it was set on a 2. According to the back of the tac, it should be set there for this boat. It was broke down like this:

1= 4 cyl.
2- 6 cyl.
3- 8 cyl.

The engine never seems/sounds like it is overreving on the occasion that you run it up in the 5000's, so this is confusing to me. Is moving to a larger pitch like that a good move, especially if you are already running a 23?

 

[cooter2506]

Re: 1994 Bayliner 1850 Prop

If you have a spare prop(as you should anyway) I would put that on and see if your results are the same. If they are then I would still verify the tach using a shop tach. If th e tach checks out I would move up in pitch. Im running a 21pitch on mine. We have about the same size boat. I should e running a 23 pitch my rpms are at 5200 WOT. But I never run it there. I max it out at around 4500. But usually just cruise at 3400rpm. I do LOVE the hole shot the 21 gives me though. Good luck and keep us posted.
The reason I want you to try a spare prop is you might have a slightly spun prop causing high rpms