Mercruiser 898, GM 305 TACH Problems

[pogi]

So I'm out on the water and I notice that my tach is not reading correctly, it's kind of jumping around. By the time I got back to the dock the motor died and there is now no spark at the coil wire. Could the TACH be the problem as in grounding out the coil? Thanks.

 

[littlebookworm]

Re: Mercruiser 898, GM 305 TACH Problems

Easiest way to check is to disconnect the tach wire at the coil. If the engine starts and runs, your tach or wire has shorted out. Turn the engine off; reconnect the wire; disconnect it from the tach; and start your engine. if it now runs, your tach is bad; if it doesn't run, the wire is shorted somewhere. Repair or replace as necessary. (My gut feeling is that, if anything is shorted, it'll be the tach, not the wire.) Good luck. Hy

 

[nmastroianni]

Re: Mercruiser 898, GM 305 TACH Problems

Definitly sounds like your coil possably failed...but besure to check the oil pressure switch. Pritty much all ingnition systems are tied into a oil pressure switch. Their is the oil sender which is for the gage and then their is the switch. I had a problem like this and it was that the wire connector came off the switch. Check for the switch on the back of the block right over by were the intake manifold ends on the right side.

 

[achris]

Re: Mercruiser 898, GM 305 TACH Problems

Definitly sounds like your coil possably failed...but besure to check the oil pressure switch. Pritty much all ingnition systems are tied into a oil pressure switch. Their is the oil sender which is for the gage and then their is the switch. I had a problem like this and it was that the wire connector came off the switch. Check for the switch on the back of the block right over by were the intake manifold ends on the right side.

No oil pressure switch on these engines.. The oil system has no connection whatsoever to the ignition system (apart from the fact that the tacho and the oil pressure gauge use 12 volts).

Do as 'littlebookworm' says... He's on the right page....

Chris.....