225 omc performance upgrade

[waterboymuz]

Hi guys I was hoping for a little bit of advice on where I should go next with my 95 225hp Johnson on an Allison GT20, here's the guts.
Boat sank a couple of weeks back, been on the bottom for 8 days and then I finally got it salvaged. I have completely stripped the motor for a rebuild as I have a spare power head that I can put on until I have rebuilt the drowned one.
I was thinking about trying to squeeze some extra HP out of the engine without going too crazy, what are you OMC guru's suggestions on what to do to get a few extra horses? I have a jack plate with 6in set back, low water pick up and am turning a 48-7577a-26 Chopper.
Thanks

 

[Jon]

What kind of water did you lose the motor in? Any salt in it? How did it look when you pulled it out?

I've only ran smaller OMC stuff, so I do not know anything about the larger ones, but maybe one of the racers on here may know. I was going to say "I don't know anything about Johnson's", but I want to avoid all the joking on your first post

 

[GotMyAlly]

I think Buddy always used pig putty to squeeze more HP out of his OMC.

 

[waterboymuz]

What kind of water did you lose the motor in? Any salt in it? How did it look when you pulled it out?

I've only ran smaller OMC stuff, so I do not know anything about the larger ones, but maybe one of the racers on here may know. I was going to say "I don't know anything about Johnson's", but I want to avoid all the joking on your first post

It went down in the Swan River in Perth so a bit of a mixture of salt/fresh motor is in great condition no corrosion and still hone marks and very little wear in the bores. It was under water for 8 days. I have another complete powerhead with low hours ready to go on so can take a bit of time with rebuilding the drowned powerhead, I don't want to go overboard with performance as it is only a recreational ski boat but i've been told those motors respond well to a good port job so if you or anyone can confirm this as well as what would be my best bang for buck parts I should upgrade that would be awesome.

 

[SLOmofo]

If you do not want to go crazy, do not look here.
http://www.davebushracing.com/johnsonevinrude-products.html
http://www.davebushracing.com/media.html
The next go round. E-Tec front half .

 

[glassman]

Hi guys I was hoping for a little bit of advice on where I should go next with my 95 225hp Johnson on an Allison GT20, here's the guts.
Boat sank a couple of weeks back, been on the bottom for 8 days and then I finally got it salvaged. I have completely stripped the motor for a rebuild as I have a spare power head that I can put on until I have rebuilt the drowned one.
I was thinking about trying to squeeze some extra HP out of the engine without going too crazy, what are you OMC guru's suggestions on what to do to get a few extra horses? I have a jack plate with 6in set back, low water pick up and am turning a 48-7577a-26 Chopper.
Thanks

Here is what I can suggest that you can do while working with your local shops, vendors, etc. Back in the day (like 20+ years ago) we had a bunch of guys running 200XP's and 225's. Our simple cheap (and good) setup was gutting the air box, rejetting the carbs, cleaning up the ports and cutting the heads. You can get a nice gain by just having a skilled porter just clean up the mess OMC left in your block. I am talking no changes to port heights or shapes, just clean up the mess. Take everything inside the air box and throw it away and install the air box empty. Lastly send your heads in for a shave. We cut ours .040, .060 and even .100 thou. I think mine were cut .060, but my neighbor had his cut .100! Lastly as I recall the carbs came with .062 main jets. We needed .076 jets after these changes (we are at 2200' above sea level). Just to be clear our motors were 1988-1992 vintage, I think your 1995 is the same. You will be impressed what these changes will do. We would gain like 500rpm doing the changes listed above. And did I ever beat LOTS of Mercs!!