225 Merc Pro Max Question.

[scott reierson]

Looking to run a used stock Merc 225 Pro Max powerhead with maybe 200 hours. I would remove the oil injection, gear and stabilizer box. etc. I would keep the factory limiter on the EFI box. This is for pleasure use on a Vector with a 15"mid.

I have previously owned several of these engines with mild mods, fresh internals, and upgraded steel caged rod bearings.

Do any of you know how long, or how many hours the plastic rod bearing carriers last in a stock 225 Pro Max?

I just want to drop on and run this engine without having to go through it.

Also, I plan to run this on a Custom 15" mid (Stock 20" cut to 15") with no exhaust relief under the cavitation plate or out the back. With the correct tuner, will this stock powerhead run ok with no exhaust reliefs with the exhaust just going out thru the gear case?

I have run cut cases before...So I know all about the potential pitfalls from that.

Thanks
Scott

[90 5.0]

I had one on a 15” mid that went upwards of 400hrs with 150psi heads and saw 76-7800 rpm before it let go. And it let go because an injector driver failed in the ecu and burnt a piston.


I wouldn’t recommend beating on a plastic cage motor like I did but it took it.

as far as the exhaust goes, if you are keeping it below 7k it will be fine.

[Capt.Insane-o]

Scott the ethanol in the gas softens those plastic cages. I will not run a motor with those bearings in it.

[scott reierson]

90 5.0 and Capt. Thanks for the feedback, much appreciated.

I've always had good luck with the 225 ProMax. It will have more than enough power for what I want to do in this application. My hope is to run it stock as mentioned above. I may try to keep the noise down running the exhaust just thru the gearcase.

Hey Captain...Thanks for the tip on the Ethanol. I have seen plenty of damage it causes. If you don't mind, please send me a PM with your number. I have some 15" I6/Vector questions to ask you.

We have Non-Ethanol gas in my area and thats what I use. Have not had any Ethanol related issues in any of my stuff yet. I do test it here and there. So far so good