225 Pro Max - Time to Rebuild?

[Powerplay25]

What are your thoughts on rebuilding a 225 Pro Max. The year of the motors are 2000 and they have 412 hrs. on them. They run perfect, compression is good. I wonder if I'm running on borrowed time. Was thinking of sending out this fall having them completely redone.

Comments?

[Jay Smith]

The Pro Max engines are a very good long distant runner. One of the ONLY concerns and from what I witness the root cause of MANY Pro Max failures is locater pins in the side pinned pistons. Its NOT a question of if they ( the locater pins ) come out its when....I rebuild them a lot and after that "issue" is resolved they have a very long trouble free service life. If you ignore this issue it will sooner or later cause you big $$ and extended time off the water compared to a simple rebuild...

good luck,

[Powerplay25]

Jay,

I appreciate your input. With the hours on the motors are the locater pins about due to be replaced? I don't run the boat real hard. Mostly cruising with the occational blast.

What do you recommend to be replaced with a simple rebuild?

[Jay Smith]

David ,
Thats like asking me to predict the stock market rise and falls ( wish I could I would'nt be working for a living ) as to predict a locater pin failure. I've seen them fail as early as a month after a rebuild with NEW side pin pistons installed and I've seen them seaming last for ever BUT why take the chance ? Most of the time if you've got my luck the thing will fail at the absolutly worst possible time either in the beginning of boating season and or when money is the tightest !!!

IMO a "normal" rebuild for most is to tear down and inspect all suspious parts and replace those that have a tendency to take the most abuse also those that its just common sence to replace while engine is down , such as top bearing, all seals, "O"rings, piston rings, have injectors cleaned and serviced, small end needle bearings, and pertinante gaskets...Mic bores for egged shapes and mic pistons for wear( If your using them again) , check piston ring end gap and adjust if needed, use the proper hones and honing methods with a correct grit and crosshatching method for the rings your using...then THOUGHLY clean and re assyemble and torque to proper OEM specs using the proper grade thread lockers and sealants...

I normally go a bit farther and replace ALL bearings have pistons top pinned to prevent future failures ( this is something that I insist on and if the customer does'nt agree they find another builder, I refuse to install a known bad actor into an engine and jepordise an engine and my reputation ) I also have the ECU sent out for a checkif suspect. I also HIGHLY suggest that the customer while the power head is here having a COMPLETE water pump kit installed ...I also replace fuel lines ( to fuel injection specs ) , vent / bleed lines, and water all hoses...Using ty straps or hose clamps on all hose to barb connectors...Test run here @ JSRE for an hour setting ECU's , timing and final retorque of heads check for leaks shrink wrap , crate with break - in instructions as per type of engine rebuilt with suggested oils and fuel octane that is needed for successfull long engine life , furnish a second set of plugs (to replace after the break in plugs have taken a dump do to oil and grease contamination at break in initial running).....

Good luck,

[Powerplay25]

Jay,

Thanks again for your input.

[Cp]

David,

Jay, as always, is giving the straight scoop. I had one blow a long time ago, and was told a plastic/phenolic reed cage failed. Hopefully, Jay can say whether this is possible or likely. Not sure to this day if I believe it, but that's my nature.

So.... Just how does a 25 Powerplay run with Promax's?? I've always thought they were great looking and properly constructed vessels.

[Jay Smith]

David ,
My "guess" ( Can't tell without a ferensic inspection) would be most failures of the reeds and or cages happen after another mechanical failure first sending pieces through the cage or allowed very hot combustion by a damaged ring into the intake track and caused an intercrankcase explosion or fire and that damaged the reed system. BUT I have also seen reeds fatiuge or fail causing an incorrect or inadiquit lack of fuel and oil vapor to be compressed and driven up to the piston skirt and crown and with that lack of lube and coolant the piston will very quickly gauld , stick, and or detonate.( The top piston speed a 2.5 can produce is 120 time to TDC a second so things happen VERY quickly ) I often get tickeled when folks "think" an EGT gauge can protect and engine giving enough "warning" that an engine is failing soon enough for the operator can take they're foot off the gas, kill the keyand stop or prevent the damage , buy the time that gauge detects an issue and signals so that a driver can see it at the dash and react that motor has BEEN blown up 1000 strokes ago...They are OK as a tuning tool BUT thats IT !

After one of these 2 stroke engine failures " Train Wrecks " its simetimes imposible to determined what happned first....Its kinda like the old saying" what came first the chiken or the egg " After the aftermath sometimes its becomes anybody's guess, that is the reason you hear SOOO many "fixes" are unsuccessfull , as those that rebuild don't have the experiance to trouble shoot the likehood of the problems, they sadly repair , reasseble and often have the same bore self destruct as the "problem" that caused the first issue is still present and has'ent be found and corrected....

BTW: Thanks for the kind words, I do my best to try to NOT candy coat the truth , if people want sunshine blown up thier keester till they float like a baloon don't read my posts or call JSRE cause I ain't that kinda guy ...

[HighVelocity]

I know how Dave's boat rides as a passenger. It rides big! and the motors do free spin alot, so maybe he should get them rebuilt soon. LOL Just kidding Dave. The best is when the boat comes out of the water, when it lands your pushed back in your seat hard. Good "Stuff".

Does a lighter flywheel equal longer run life of the motor or just better performance.???

[Jay Smith]

IMO lighter flywheels give longer life to Mercdury sub par bearings and also helps acceleration..

[Powerplay25]

Cp,

I love the ride of the boat it handles the ocean very well for it's size. The boat is built very strong for rougher water. I wanted something that I could run in the bay and take outside and run down the coast. The mid-range acceleration with the twins is fantastic. Huge difference from moving up from my last boat (21' Checkmate).