Logo

Probably looking at a mess, but let's look anyway.

carogator

Regular Contributor
Mod.# 5073M -- Found a decent deal on a wider more stable boat. However it comes with an engine problem. The head is already off and shows signs of something hammering on the top of piston. Left little square marks like a broken lock washer piece (as wide as it is long) 1/8th " maybe. I found that the engine will
rotate, both directions, almost exactly 180 degrees and stop. The pistons move up and down as they should. I'm guessing that something broke and came in through the holes in the cylinder walls.` Appreciate any ideas or suggestions.
 
Is it possibly Model #50473M? 5073M doesn't seem to show up in a search.

A shot-peened piston dome means a ring broke off, a piece of bearing (or cage), or a piece of a reed valve has come loose and gotten sucked into the cylinder where it bounced around and smashed against the piston until it was spit out through the exhaust port.

The fact that it turns 180 degrees then stops says there is an obstruction still in the engine that is catching and preventing free movement.

You are looking at a complete tear down of the engine to inspect and replace all worn and/or failed components. Depending on your skill level you might be able to rebuild the engine just for the price of parts. Is the boat super cheap leaving you plenty of head room to do the rebuild? If not, walk away because there are plenty of boats for sale in running condition.

If you're in the US, boating season is coming to a close and many owners sell in the fall not wanting to bother with storing it for the winter. In other words, this time of year is a buyers market. I'd suggest you keep searching and I bet you'll find a good deal on a boat that doesn't need a complete engine rebuild.

KJ
 
You are right, it is 50473M. I didn't catch that on preview. I already bought this outfit at a great price, with the knowledge that the engine had a possible major problem. The head already off, there were no surprises. Seller fully informed condition. I believe you nailed it with the broken ring. The size fits. I am already looking for a 40 or 50 HP to put on it.
Just looking to see if this could be fixed reasonably. Thanks for the jump start.
 
...I already bought this outfit at a great price,....I am already looking for a 40 or 50 HP to put on it.
Well, I guess you're on your way.

That style of 40/50HP 2 cylinder engine was used for a long time. Hopefully someone knowledgeable of the specifics of this model will check in and confirm, but if the lower unit is in good condition you might have options to swap it onto another engine. You might start search for 'parts motors' that have a trashed lower unit and you could put yours onto it.

I wouldn't try to frankenstein anything and I would only look for a powerhead & midsection that are an exact fit for your LU. If you can find that it might help you keep this boat on a smaller budget.

Or, option #2 would be to sell your LU if it's in good working order, sell off the good parts of your powerhead, and use that $$$ to fund the purchase of a newer, good condition outboard.

KJ
 
Back
Top