2003 Tohatsu MFS9.9B2 3V5 throttle high pitch whine

[keith23464]

Hello there. I have a 2003 Tohatsu MFS9.9B2 3V5. It a center console outboard. The throttle box on the center console I believe is supposed to make a high pitch noise when you put it in reverse. A few months ago mine starting making a high pitch noise in forward or reverse. It doesn't make the sound when the throttle is in neutral. Any ideas?

 

[Sea Rider]

Probably the engine cable link that gears forward and reverse by means of control box is not properly adjusted. Remove it and manually move gear forward and reverse and check if doing same. If not, re adjust cable linkage to engine.

Happy Boating

 

[keith23464]

Sea Rider,

Thanks for the suggestion. Do you know where instructions to adjusting these cables can be found? I have the owners manual PDF for the Tohatsu and it is woefully devoid of any detailed instructions on how to do any adjustments or work on the motor. I was also planning on replacing the impellor in the near future and couldn't find and information on that either.

Respectfully,

Keith

 

[keith23464]

If I turn the key to the on position but do not start the engine, the box is quiet. But if I pull the engagement handle and move the throttle into either forward or reverse, the throttle box makes a loud constant beep. It does it if the engine is running or not. I thought it was supposed to be a backup warning beep but I fear that it is some other type of warning. I cannot find any reference to why the throttle box would beep.

 

[pvanv]

It is not a reverse warning. It is the warning horn. Is the oil pressure warning lamp on?
The Factory service manual is available from any dealer.

 

[keith23464]

No the oil pressure light is not on and I checked the oil level and it is fine.

 

[pvanv]

Then you have either a wiring problem (such as a wire that has shorted to ground) or a defective CD. The 2 things that CD monitor are oil pressure and over-RPM.