1986 Force 125 low RPM's?

[watersport 1]

Hi all I'm new to this post.
Is 4100 rpm's at full throttle too low for a 19' foot trophy bayliner center console? If yes, how can I improve the rpms?

 

[tjello327]

Re: 1986 Force 125 low RPM's?

Sounds a little too low. It depends on the prop pitch that you are using. I have a 17' Larson which has a pretty deep v and is pretty heavy for its size. I also have the 1986 125 hp Force. I had a low rpm issue at one time and it ended up being the floats in the carb starving the fuel to the engine. I set them to book specs and picked up rpm. The fuel pump, fuel lines, ignition timing, low compression and bad fuel are a few common other conditions to be aware of. I had a 19 pitch prop on my boat and went to an 18 pitch and gain a few hundred rpm.

 

[87blf125]

Re: 1986 Force 125 low RPM's?

i have an 18ft bayliner bass and it runs the same as yours about 4100 with a cupped 19 pitch alum prop i dropped to a cupped 17 pitch stainless and now run around 5000.

 

[foodfisher]

Re: 1986 Force 125 low RPM's?

The RPM's match the motor not the vessel. '86 125hp force should run 45-5500 rpms. wot. Closer to 5500 is better. Fine tune, then prop.

 

[sho3boater]

Re: 1986 Force 125 low RPM's?

If the prop is damaged at all it can affect rpm, if you have not run it with a good prop. Synthetic LU lube will give my 85hp about 100rpm.

 

[john from md]

Re: 1986 Force 125 low RPM's?

The rpms you are seeing look more to me like it dropped a cylinder rather than the propeller. Try pulling each wire off in turn at idle and see if one doesn't make a difference.

John

 

[watersport 1]

Re: 1986 Force 125 low RPM's?

The rpms you are seeing look more to me like it dropped a cylinder rather than the propeller. Try pulling each wire off in turn at idle and see if one doesn't make a difference.

John

Hi
Do you mean take one of and replace, then take the next one off and replace etc... or take one of at a time until all are off?

 

[john from md]

Re: 1986 Force 125 low RPM's?

Take one off and replace then take the next off and replace. I'm betting you will find one that, when you pull off, there is no change in the engines operation. That tells you that the cylinder is dead either from no spark, no fuel or damage to the rings.

John

 

[watersport 1]

Re: 1986 Force 125 low RPM's?

Take one off and replace then take the next off and replace. I'm betting you will find one that, when you pull off, there is no change in the engines operation. That tells you that the cylinder is dead either from no spark, no fuel or damage to the rings.

John

Thank you. I will check.