Tach reads wrong at start-up

[Wylie CC]

I have a 2000 Chris-Craft with a Volvo 5.0 GI and SX-M drive. When i start the engine, the tach will read over 2,000 RPM, but when I tap the tach, it will jump up to around 3500, then tap again, and it goes to where the engine is idling. Then it is fine until i shutdown, then it occasionally does it again after a warm start.

Could this be a bad electrical connection? I have verified that the tach is set to 8cyl on the backside.

I am a newbie so wasn't sure if this goes in this forum or not.

 

[Don S]

Re: Tach reads wrong at start-up

Probably corrosion inside the tack itself, and will probably get worse. Might try turning the set screw where you set the tach to 8 cyl., back and forth a few times and see if it helps. New tach is the only sure cure.

 

[Bondo]

Re: Tach reads wrong at start-up

Ayuh,... It's on it's way Out...
The twist the switch trick works for awhile, as the thumpin' with yer fingers...
Eventually, you'll be buying another 1....

 

[wakina]

Re: Tach reads wrong at start-up

Had the same problem three years ago, acted the same way. Replaced the tach and have not had a problem like that since replacement.

 

[PuddleJumper]

Re: Tach reads wrong at start-up

When I used to be on the Regal forum it was lovingly referred to as the Faria Tap ;-)

 

[Tail_Gunner]

Re: Tach reads wrong at start-up

http://www.faria-instruments.com/site_manuals/IS0090_Faria_Marine_warranty.pdf

$30.00 to rebuild...pretty cheap for marine

 

[madurodave]

Re: Tach reads wrong at start-up

May i ask what setting is the 8 cyl? Which contact, 1st, 2nd, or 3rd? Just curious.

 

[Bondo]

Re: Tach reads wrong at start-up

May i ask what setting is the 8 cyl? Which contact, 1st, 2nd, or 3rd? Just curious.

Ayuh,... Usually the 1 that says "8"...

 

[Wylie CC]

Re: Tach reads wrong at start-up

Thanks so much for the info. I guess I will try to hold out until it goes, then look into rebuilding it to try and keep the guages all the same.

"Faria Tap" I like that.

You guys are great