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View Full Version : Twin 225 outboards on a 35ft Burnscraft



Jaredkemp
06-03-2015, 01:17 PM
I have a 1971 35ft burnscraft. Twin 318s that are coming out, outdrives are rough and transom needs to be done. I found a pair of merc 225 outboards for a steal of a deal. I plan on glassing the transom and reinforcing it. Adding a bracket and these motors. Are they to big? Do you guys think it will work?

boatlover
06-03-2015, 03:50 PM
Yes it will work. There used to be a 38 Holiday Mansion with twin outboards here in Pgh,Pa.

OLD HOUSEBOATER
06-03-2015, 07:24 PM
Depends on the gear ratios and size of the props on the outboards. If the out boards were set up for a lighter boat they will just spin out on the BC. If they were on a heavy boat with large diameter props your probably ok. The 318s were probably spinning 3 or 4 blade 20 inch with a 16 /18 pitch or bigger.

I would rebuild the 318s.

Stmbtwle
06-08-2015, 09:31 AM
Agree the size of the props is important. Depending on the boat the motors were on before, you'll probably need new props anyway. Get the biggest diameter that will fit those motors and a much lower pitch.

How fast do you really feel you need to go? You could probably do quite nicely with ONE outboard, and sell the other or keep it for spares.

Endurance
06-08-2015, 04:19 PM
I think you'll do fine. My guess is that you will end up with props in the range of 13 pitch to 15 pitch. I had 9 pitch props when my boat had 50 hp outboards; I changed to 11 pitch when I replaced the 50 hp outboards with 115 hp outboards. My boat is 65' x 18' with aluminum pontoons. With 225s on a 35' boat, you won't be underpowered. I think I would err on the side of being slightly overpropped rather than being slightly underpropped to get good fuel economy out of the 225s.

I bought Propco propellers and I'm glad I did. They sell a reverse hook cup propeller for houseboats. They claim that the reverse hook cup increases reverse thrust by 200% with no noticeable effect on forward thrust. I have gotten used to inflated marketing claims, but this one seems legit. My experience is that, if anything, the 200% reverse thrust figure is understated. That's huge for maneuvering around docks, especially in wind. I have no ties to Propco except that I own a pair of their props. I have found that they have things not listed on their website so I'd call them if they don't list reverse cup hook props for a 225.