Merc 2.5L on Seafari?

[muddywater]

There are lots of race motors for sale over here right now. My question to you, is how are you guys putting them on your boats, they all have 20" or shorter shafts. Have you guys not raised your transoms or mounted it on a lowered jack plate or something?

The reason I ask is that I have a 1980 115 Mariner/Merc inline 6 at 278lbs which is about to come off the boat this week so I can rebuild the transom. The original owner claimed it had 17 hours on it and the lower unit looks like it could be brand new except for the faded paint on the whole motor. I just tested the compression and it was 130 across the board if my cheap tester is not lieing. Besides the fact that it needs a switch box ($280 to buy 2 since you have to install in pairs), is it even possible to mount this or one of the 20in shaft racing motors on a 25in transom with a jack plate or is that just a bad idea?

[McGillicuddy]

That's an interesting question. I had thought about raising transom and using a jack-plate instead of a bracket also. The only problem I saw with the lowered jack plate idea was not being able to tilt the motor up fully. Also considering a 5" drive extension from Bay Mfg.

[fdheld34]

If I were to raise transom to 25" and had 20" shaft..I would want to purchase 5" extension as well...keep motor as high up out of water as possible especially when in the ocean. Also, purchasing a 20" shaft motor from bass boat will usually be corrosion free (especially tiller arm bracket etc from me shopping around last year) and then add 5" extension when time comes to enclose/raise transom. Seems to me that you would be defeating the purpose of raising transom to 25" and then use a jack plate to lower engine. Or you could buy a clean 25" shaft motor and use a 2 piece fixed height jackplate on your 20" transom until you enclose/raise transom (watch that waterline though...did it on a 18' formula with a 150). I think I am getting off topic..my apologies!!
-Fred

[Bigshrimpin]

Hey Fred - Have you run that 135 on your seafari yet with the bracket? Any noticeable speed difference?

[fdheld34]

Big-
I still have to do rigging etc...will be a while...also need to figure out what prop to run...
Will post numbers in future though!!!
-Fred

[seafari25]

Looking sweet Fred.