1994 3.0 mercruiser

john diebolt

Cadet
Joined
May 11, 2009
Messages
10
My nieghbor has a 1994 Mercruiser 3.0 that is hard to start when the engine is cold. Also during driving conditions the temp. guage will read 140-160 and when he pulls 2 tubers the temp. guage will rise to 200. Do you have any suggestions?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,480
Re: 1994 3.0 mercruiser

If it has a carb, you`ll need to pump the throttle once or twice before starting. Only pull 1 tube or try replacing the impeller in the lower unit. After the impeller is replaced and the problem persists, riser replacement may be required.
 

john diebolt

Cadet
Joined
May 11, 2009
Messages
10
Re: 1994 3.0 mercruiser

I as wrong imagine that.. My neighbors boat does not have a starting problem just an overheating issue..Yesterday he pulled one knee boarder and the persisted. He is thinking of pulling the lower end and replacing the impeller then relacing the water pump. Is this wise?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,480
Re: 1994 3.0 mercruiser

Impeller first, there only good for 2 years, regardless of use.Riser may go 5-6 before starting to clog up from scale .hi-speed overheats are a classic condition but do have other causes. The circ pump on the engine rearly goes bad, may start leaking but thats all.
 
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