225 ProMax -- Shake at Idle/Low RPMs Normal or Excessive?

[jign4pigs]

Hey all,

SN# 0G367609 (1996)

Bought this boat last spring. Always thought this was just how the motor was, and that may well be so figured I'd ask here:

Motor seems to shake to the point where you can feel it in the whole boat at times. I read through some similar posts but most of them had to do with engine stalling once throttle was applied. This engine works fine once on plane.

As part of a different repair, fuel injectors were sent out and cleaned this winter. No obvious evidence of prop/propshaft issues (23P Temp + w/Large PVS plugs). No issues with stalling just has a rumble/shake at low rpms. Below are some links to a few short videos on my google drive. Not sure if it will really translate well in the video.


https://drive.google.com/file/d/18Kf...ew?usp=sharing

https://drive.google.com/file/d/18JH...ew?usp=sharing

Thanks for any insight

[JOE54]

solid mtr mounts/may need tune up with all sensors tested and timmming set up ,might be lil on the rich side low speed

[EuropeanAM]

+1

Essentially a race engine... not a lot of effort spend on making it "smooth as silk" at idle speed (built with the "go fast, turn left, go fast again" mentality).

[1Holeshot]

I agree with Don. When I had a 225 Pro Max on my Allison 2003 XB, I did not do much idling but a lot of WOT unless water was too rough.

Still my favorite engine until I got my current one.

[JaySmithRacing]

My 225 PM rebuilds idle SMOOTHER than stock , BUT after our builds they are balanced and tuned ,extracting Max HP from any of the V-6 2.5’s is our special nitch .. Give us a call @ 832 597 2603 and I’ll separate the myths from facts on these engines , we are in Jasper Texas
www.jaysmithracingengines.com

Jay @ JSRE

[silverbullet02]

Doesn't look too unusual to me. If you don't have a manual, you should pick one up or borrow one, it might be worth it to go thru the whole link n synch procedure just to make sure everything's where it's supposed to be. That'll cure many issues more often than not. Sometimes people mess with them, and I often find some put too much initial timing in them, never liked how they idled like that. I usually set mine up around 3-5 ATDC and full timing at 23. A lot of people say you can run 25 degrees, but I pull it back a couple just for peace of mind, never really know what fuel you're getting sometimes. That's just the way I've personally found that I like. Not sure I'd put it in the race motor classification, mine will idle at 600rpm all day long nice and smooth. Also, as mentioned above, the solid motor mounts transmit a little more vibration to the boat than what you may be used to, but solid mounts are the only way to go.