Logo
FULL SITE MENU

Optimax 225, bent rod

K

keepfishin2

New member
First time posting. I have a 2002 Optimax 225 with 200 hours. boat ran great last trip out. A couple of days later I started boat at dock and instantly motor starting knocking really bad. Started taking apart air intake plenum to inspect pistons and rods, and i noticed a few ounces of water came out of bottom of air intake. after full inspection found out I bent # 6 connecting rod. I guess the motor Hydrolocked? ......Can anyone pass along their experience or wisdom as to where or how water can enter cylinder, other than my head gasket ,which i already examined. and lets rule out cracked block, for now.
Much appreciated.
 
Bad lower crank seal? Was there water in the crankcase on that hole?

Jeff

PS: Got a nice con rod if you want it.. Cheap.
 
fastjeff said:
Bad lower crank seal? Was there water in the crankcase on that hole?

Jeff

PS: Got a nice con rod if you want it.. Cheap.
Click to expand...

this is a 2 stroke motor. when i removed the air intake a small amount of water came out. what does the crank seal have to do with water??
i believe the crank seal is for oil not water??
 
So is the motor all apart ?---------Any rust damage internally ?----Is there a chance that the launching introduced water to the bottom cylinder ?-Provide as much information as you can !---Please note that a bottom seal also keeps water from the exhaust housing out of the engine.----It is a 2 stroke engine and that is how they behave.
 
The # 6 cylinder is at the bottom of the crank, and the bottom of the crank is sealed against water in the drive shaft housing being sucked in under vacuum. (Think about it.) # 6 is the only cylinder that can have that problem. and it does.

Jeff
 
fastjeff said:
The # 6 cylinder is at the bottom of the crank, and the bottom of the crank is sealed against water in the drive shaft housing being sucked in under vacuum. (Think about it.) # 6 is the only cylinder that can have that problem. and it does.

Jeff
Click to expand...

I understand what are saying about the lower seal and #6 cyl being the lowest cyl. But why dont i see any sign of water marks or salt residue in the block, or lower part of crank? Without pulling powerhead off how do you inspect or verfiy the seal is leaking?? The only sign of water was a few ounces in the air plenum? i want to re-assemble motor this weekend but i am very concerned about another bent rod or worse this time. Not being able to confirm how water entry ocurred is a seriuos risk of catastrophic failure..and not to mention a 5k hit!!
 
Engine cowl is always on the motor. Air plenum plastic covers are always secured and not broken or cracked. Throttle is completely covered at all times.
This is very puzzling?? I am starting to think somehow, water came in from the air intake louver on the back of engine cowl, while i was hosing down engine. sounds crazy but i wonder if its possible that i sprayed water, accidently, into this engine rear air intake louver. I wash engine with motor tilted completely up so i can washdown lower unit and prop. Is it possible for the water to enter engine cover louver and trickle on to plastic air plenum cover and make into throttle plate opening??
 

Attachments

  • 20131025_135934_resized_1.jpg
    20131025_135934_resized_1.jpg
    75.9 KB · Views: 95
  • 20131025_140003_resized_1.jpg
    20131025_140003_resized_1.jpg
    72.1 KB · Views: 111
  • 20131025_140014_resized_2.jpg
    20131025_140014_resized_2.jpg
    76.2 KB · Views: 107
I agree with you, but am puzzled to how the water entered the air intake?? do you have any ideas? i certainly want to avoid this from happening again.
 
I guess you could take the cowling and put it on the ground.---Tilt the cowling as it was on the motor.-----Repeat the hose down and see if water enters the cowling.
 
Docksidemarineservices said:
Possibly when you washed he engine while tilted up with a pressurized water supply.
Click to expand...

I checked my engine cowl today and i dont see how water could enter thru the rear air louver intake. There is a rear metal deflector plate on the inside of the cowl that blocks and directs any unwanted water straight down and out. I completed the repair and fired the motor up this afternoon. Running good again with 1 new piston and rod. I just wish I knew how i hydrolocked so I can avoid another expensive and damging failure!!
 
fastjeff said:
Don't blame you. I'd stay close to home for a while until you're sure she's okay.


Jeff
Click to expand...

Thanks, after checking the design of the engine cowl cover carefully, i am now convinced its was not anything i did during normal hose washing.
i am still of course nervous and un-sure what caused it and will it happen again whiel i am at 5000rpms or at morning startup at the dock!!
 
Back
Top