Over last winter while in storage I had my batteries replaced on my boat. The batteries were replaced with deep cycle Interstate units. Recently had a mechanic on board who advised me that using a deep cycle on a 496 (8.1) inboard horizon Mercruiser to start it will damage the engine's computer. I found this statement to be a little far fetched. As any 12 volt battery puts out roughly 2.2 volts per cell, I just can't believe the mechanic. Would appreciate some input on this one. Thanks..

i have deep sicle on my 496 HO 2001 for about 8 years never got a problem,boat i s about 500 hours.

Deep cycle Interstate in mine with a 496HO 300Hrs starts fine every time.

As long as they start the engine, they are fine. A deep cycle just doesn not put out as many CCA's.

Thanks for the replies. I figured I was being stroked big time especially after the same outfit charged me $16.95 (parts only) per platinum sparkplug for a plug Autozone sells for $3.99 !!!

That is Merc retail price for the sparkplugs .......which is nuts.

Theres some good threads on here about plugs too.

Yeah, thats a legitimate price for the plugs. My marine store has then at exactly the same price.

exactly right

find another mechanic....