Tachometer Reading 1,000 rpms High??

[Solittle]

I usually fire up both engines (1987 OMC xflow V4s) every couple of weeks here at the house to keep them lubed and fuel going through the carbs. This afternoon the starboard tach was reading about 1,000 rpms too high (2,400 rms vs 1,400). The tach seemed to increase and decrease normally as I raised & lowered the throttle.<br /><br />It was getting dark so I didn't fuss with it. Any pointers on where to start troubleshooting?

 

[Joe Reeves]

Re: Tachometer Reading 1,000 rpms High??

With your past experience with the engine, knowing what 1400 rpm sounds like (and comparing it with the other engine), was the rpms actually 2400 rpm or was the tachometer giving a false reading?

 

[MCM]

Re: Tachometer Reading 1,000 rpms High??

Verify whether the problem is with your tach or motor using a tach/dwell meter.

 

[Solittle]

Re: Tachometer Reading 1,000 rpms High??

I have had this rig for a number of years so I am familiar with how it sounds - sounds like 1,400 rpm but tach reading 2,400rpm. The tach on the other engine is reading as it normally does.

 

[MCM]

Re: Tachometer Reading 1,000 rpms High??

SoLittle, I'm pretty sure there's not much I can add that you don't already know, that said, the only thing that comes to mind is if you're using a universal tach is there a chance the setting got changed from say 6 pulse to 5 inadvertantly which would give you a higher reading?

 

[Paul Moir]

Re: Tachometer Reading 1,000 rpms High??

How hard is it to take the signal line off one tach and put it on the other?

 

[Solittle]

Re: Tachometer Reading 1,000 rpms High??

Thanks Paul - I should have thought of that.