225 Promax Smoked Piston Need Advice

**TNRoostertail** · 10-23-2019, 06:36 PM

Buddy just bought a beautiful 209TE Gambler yesterday. It has a 99 Mercury Promax 225 on it. Checked compression, all cylinders were 118-121. Well today it was running at 5800 rpms and just fell on its face. Got it back home and ran a compression test right off the bat. Pics will show what we found. It melted the port side middle piston. My question, is it rebuild-able? The port seams to have got slapped and nicked off some of the actual engine casting behind the sleeve. If rebuild-able we will of course bore it and just refresh the whole engine. As always guys thanks for your help.

**TNRoostertail** · 10-23-2019, 06:47 PM

Fixed typo on compression numbers, it was 100 not 200 lol.

**patchesII** · 10-23-2019, 08:12 PM

Looks fixable to me. Try to find James Perry for machine work. Pretty sure he’s in Tennessee.

**mrichartz** · 10-23-2019, 08:20 PM

I'm sure it could be re-sleeved, unless there's more damage that can't be seen in pic
And x2 James Perry and he is in Tennessee

**Merc 2.5** · 10-23-2019, 08:44 PM

Yes very rebuildable , injector prob stopped up , unfortunately I tried get James take a block and he not taking any blocks at moment ,texas20225 also talked to james and told him same thing. He just to busy. Chris Carson would b another I would trust and he has good turn around

**TEXAS20225** · 10-23-2019, 11:05 PM

yes its do able ive owned 9 225 promaxs i built rebuilt all of them but thats what i did for a living!!! its number 4 the most failed cylinder in all of my rebuild experience ( over 400 motors) its also one of the hottest holes next to number 5 i owned several pmaxs that i had all six sleeves replaced because they get a load of abuse James Perry is the best machine shop man i ever used ever . i havexa 200 (original block) oring head that he turned into sumtin

it the best promax wanna be ive ever had it a lot stronger then a stock 225 but its had lots of port help along with some other "stuff" if your in no hurry call james and tell him u want in line u wont be sorry

**bullet123** · 10-24-2019, 04:34 AM

Did promax come stock with the diverter tubes ?

**tux974** · 10-24-2019, 04:44 AM

Originally Posted by bullet123

Did promax come stock with the diverter tubes ?

Yes!

TNRooster, block looks to be an easy fix from pics but pics could be deceiving. Certainly James Perry or Chris are good guys!
Hopefully the small debri has not travels around the inside and hurt anything else like crank etc.
BTW, I suggest to get rid of that stabilzer next time around.

**LakeFever** · 10-24-2019, 06:20 AM

That’s quite a chooched piston, how long did you run it after it fell on its face?

**TNRoostertail** · 10-24-2019, 07:54 AM

We have a 1984 175hp blackmax available to us. Could we hang that motor for the time being on the boat without swapping controls? And thanks so much guys for your help.

**TNRoostertail** · 10-24-2019, 07:56 AM

Originally Posted by LakeFever

That’s quite a chooched piston, how long did you run it after it fell on its face?

About 5 - 10 minutes, just to get to the dock. The motor never shut down just lost power. He did the right thing and went to the ramp immediatly.

**TNRoostertail** · 10-24-2019, 07:57 AM

What is the stabilizer? Thanks

**LakeFever** · 10-24-2019, 08:27 AM

Theres not much different between the carb and fuelly motas as far as rigging is concerned the 175 should be a very straight forward swap. Powerhead swaps are a little more involved with gaskets/plates/covers etc that have differences that go beyond my pay grade of knowledge. If the block and bore are not cracked im sure that rebuild would be straight forward. New pistons/bore/gasket kit and have someone who knows whats what check out all the non published known areas of concern and the ProMax will be good as or better than new

**bullet123** · 10-24-2019, 08:50 AM

Originally Posted by TNRoostertail

What is the stabilizer? Thanks

Rectangular box bolted to side of block.

**TNRoostertail** · 10-24-2019, 10:07 AM

Good deal, thanks guys. I know the throttle and shifter will be the same. The promax has hydraulic steering, should be a bolt up deal. The only thing that idk about is the pin connector for the engine.