SUzuki DT15 made a knocking sound then died

[Jcoyne97222]

I put the boat in the water the other day. Motor fired right up. I was idling at the dock in neutral while everybody got in and the motor started with a light knocking sound. It died shortly after. When I pushed the starter button it was froze up and wouldn't turn over. I put it back on the trailer and for the hell of it pressed the starter button and it turned over. Are there other things to look at that would lock the motor up like this or does it sound more like a motor seizure? Can the water pump seize up like this?

[99yam40]

I have seen a DT150 lower unit lock up because of the drive shaft bearing had no lube. It did turn over again after it cooled off.

Not sure if the DT15 would do the same thing

[Jcoyne97222]

Would tthis happen sitting at the dock idleing?

[99yam40]

Lets put it this way, you have to start trouble shooting what locked up the motor. check the lower unit or look at the cylinders and pistons . It is up to you which you do first

[Jcoyne97222]

99yam40, I opened up the lower section and found the water pump impeller with junks broken off and maybe wedged. I drained the oil out of the bottom and it looked real clear. Anything special I should look for other than replacing the parts on the water pump and making sure the passages are clear? John

[99yam40]

Never heard of a rubber impeller locking up a motor. Maybe the motor overheated because of no water flow, how long did it idle before it locked up?
you may need to inspect cylinders and pistons. at least check compression.

[Jcoyne97222]

I would guess about 10-15 minutes. Upon further inspection last night I found part of the water pump housing was cracked as well. It looks like it had been like that a while because it was pretty corroded around the crack. I will begin to source parts today and get the lower end back together and run it. I'm hoping it over heated. It cranks over just like it always has and seems to have good compression when pulling over by hand.

[99yam40]

If it overheated enough to lock up the motor it would hurt the pistons and cylinders get a compression gauge and test to see before spending money on parts

[Jcoyne97222]

Well I didn't get this post until after I spent the money. I did the mental math that even if there was more work in the motor it would still be cheaper than buying another used motor of similar use and age. This motor is very low hour and clean. Plus it's a fun project! Parts will be in next Wednesday so I will keep you posted.

[Jcoyne97222]

Ok, I got the parts and put everything together. I fired it up and it ran good and definitely sprayed more water. There was water coming out of the exhaust, back side of the lower unit where the hose from the water pump goes and just a dribble from the true tell. I ran a wire up into the true tell and it started praying pretty good. When I revved it up it seemed to clog up until I poked the wire up again. I repeated this until it was spraying pretty solid. Anybody have to do a roto rooter like this and any input on how to handle this without pulling the motor?

Thanks,

John