Repower Question

[mikepelham]

I just purchased a 31 Bertram and am going to repower with Mercrusier 496's. Has anyone converted to these engines with the down angle tranny? And if so, does it fit or do you have to modify the engine boxes or cut into the deck?

[scot]

What engines are in the boat now? If it has the big blocks with a Borg Warner reduction gear the new engine will basically be the same but a down angle gear will be 6" -10" shorter, depending on which gear you pick. I suggest you mcok up the engine/gear from plywood and see if if fits. Both the engine & gear companies will have good drawings for building the fake motor. Cost you about $20 bucks and a Saturday but could save you $$ thousands in bad decisions.

Over all length and engine placement as relates to the box, stringers and exhaust run is the issue here.

Good luck....I also suggest you try to get more fuel in the boat if you want 496's, your gonna need it.

[mikepelham]

Thanks for the info. It has one crusader 454 and one mercruiser 454. I do not even have the boat in my hands yet. They are FWC engines and I want to do a compression. They supposedly have about 700 hours each. The 496's are EFI and very fuel efficient. I did talk to a guy who is getting about 1.5-1.6 MPG. The boat currently has 310 gallons capacity.

[alano]

I replaced the 454s with merc 496 in a 35 and found the engines set further back by about 6" (messed with COB some, have got about right now) - required a bit of mods to the beds, engines were a bit thinner but height was the real concern - had to remove the insulation from the hatches and leave off the cute merc motor cover to get the req'd 1/2" clearance for the flame arrestor and computer. You have plenty of fuel, I burn the same but have picked up ~ 2kts -added 1.5" of pitch and still turn 150 over max. Don't forget the ethanol BS if it affects you. Good luck, Alan.