I have been told that the Commander 31 that I purchased has been repowered with 235 hp 350q engines.
They have the open cooling system and look to be at home in the boat.
I've come to find out that the reason the port (left) engine is out, is because it sheared the key at the end of the crankshaft. The previous owner ran the engine for quite some time after he lost propulsion on this engine. Which ruined the diameter of the crank and the bore of the drive hub.
It this point, my plan is to remove the crankshaft and weld it up. Then machine the stub back to it's original diameter.
With the flywheel forward and all the torque of the engine relying on one little woodruff key, I feel that this is going to be a problem.
I realize that there are a lot of Chris Crafts set up this way but is this a weak point in the drive line? What are your thoughts?
My comment on the woodruff key may be incorrect. It probably has a straight key.
So my question is what could possibly cause the key/ to shear?? Sounds like something else failed to cause this.
The people at the marina told me that the previous owner was extremely abusive to this boat.
They were told that this guy liked to throw it in reverse, while at cruising speed. He had four engines replaced before the 350's were installed. The guy wanted more power. PO seemed like a decent guy but he was sober when I met him. Apparently this is not normal for him.
He liked to get hammered and go out and beat on this boat. I'll bet he's single.
Anyway, the mechanic at the marina recommended that I go through the gear box, while it is out. I agree.
I paid $500 for this boat, so I do have some work to do. I'm ok with that, just knowing that I got it out of his hands makes it worthwhile.
So, I'm going to say that it is human error that caused the key to shear.
At that level of investment I would see if there is clearance to replace the engine with a normal 350.
If so do so, new, used, or?
If 350s fit, bet they will, make the change, sell the Q's at a premium, there are no new ones and they are approaching unobtainium status.
Keep us posted.
I have never heard of a key shearing off in that area. Must have been a bad owner. I've only gone thru one motor in 40 years and that was a sending unit failure. Be careful if you decide to change motor configuration as you have deck height considerations to deal with. The reason they put some of the Q engines in is because of the low profile.
I hit a rock and sheared mine off, I was able to pull the tranmission, found the damper hub took most of the beating and was able to get a new one and install on the crank with no problems, it's been about 10 years now.