951 Engine

[mccordb]

I have a 01' 951 engine that has lost some compression in the rear cylinder. I am trying to decide whether to put new crank (to fix possibly bent rod) and new .025 pistons rings etc with a bore over (to eliminate scoring on the cylinder walls) and new reed valves just because it is a 10 year old machine, or to part out my engine and buy a new one.

Anyone got advice as to which is the best option for the time and money? The ski runs great it just wont hit top RPMS and I am blaming the lost compression.

 

[Kozerxp]

If you bought a new engine (rebuilt) you would need your old engine as a core and why do you think a rod is bent is it torn down and inspected already may just need a top end and it's not that bad of a Job on the 951

 

[mccordb]

No I have not broke it down yet, my brother borrowed it and he flipped it and got water in the cylinder and tried to crank it and said it would not spin over.He even said he tried hooking it up to the truck and jumping off. When I got it I pulled the plugs out and spun it over and it sprayed water out of the cylinders. Since that day I have had low compression and it will ony top out at about 6500 rpms. I pulled the carbs outr and cleaned everything out to make sure it wasnt a gas issue. I guess I am assuming with water in the cylinder and him trying to crank it and loss of compression that it was just a bent rod.....

 

[Dr Honda]

It is very unlikely that you bent a rod. Because of the RPM's these engines run at... if it flexes, it will just break, and come out the side/bottom of the block. Chances are, you've just warn the rings, or melted the side of a piston.

As above... if you buy a rebuilt engine... you have to send them back your engine as a core. If you don't send it back... they rape you. STB will charge you about $3k for a 951 core. (on top of the $1100 for the rebuild) A good used engine will cost you about $800. In that case, you don't send back a core, and can part out your engine.

But before anything can be said for sure... take the head off, and take a look.

 

[Minnetonka4me]

If you can rebuild your motor do it. With SBTs prices (shipping is only 3 day now...big $$$) these days its hardly worth it.

 

[TheChad]

I don't know why Dr Honda thinks a bent rod would be unlikely. It's one of the most common things that happens with water logged engines.

Here's a picture of my wife's 717 PTO connecting rod...

It had 150PSI compression on the MAG cylinder, and 105 on the PTO Cylinder. It still ran good other then a small bog from idle.

-TheChad

 

[Kozerxp]

If your bro flipped it and it got water in the cyl it's more then likely that your bro flipped it back over the wrong way and its unlikely you bent a rod the starter motor is not stronge enough to bend a rod If it were me I would pull the head and take a look and pull the cyl off what do you have to lose other then a hours of hours of your time to see and if it's ok the just rebuild the top end it's easy if you have mechanical ability

 

[Dr Honda]

OK... yes... if the engine takes a mouth full of water, at speed... and it hydro-locks... you will bend a rod. (It's still not common)

After reading his second post... yes... I can see that now.

 

[mccordb]

Yeah it wasnt running when it got water in it, it would have to have been bent by the starter if it got bent. I am going to take it apart this weekend maybe and take a look at it. Are the rods one or two piece rods in this engine?