1999 Carb Merc 125 SWS

[Crackerasscracker]

I have the above (twin) motors on my 25 World Cat. They have @ 300 hours on them. This weekend, the port engine blew very far off shore. The fly wheel was seized. When we finally got home, I took the plugs out and saw plenty of chunks of metal in the 2nd cyl. Further inspection of the engine found more chunks of metal stuck to the cowling and other parts of the motor surface. I took the starter off and was able to see that the oil tube going into the #2 CYL had split at the base where it went into the cyl. It appears the only thing holding the oil tube into the barbed fitting was the male barb fitting itself. No nylon ties or ss worm gears. I looked at the other engine and found this to be true on both. This seems like a very poor design. There is no way for you to know when this fails until the motor seizes. Anyone else have this problem?

 

[WillyBWright]

Re: 1999 Carb Merc 125 SWS

Welcome to iboats and that's not an oil line.<br /><br />It's a recirculation line that takes puddled fuel and routes it to where it can do some good before being burned-up and expelled out the exhaust. It's only a tiny portion of what gets burned. I doubt that caused your problem, but I suppose it's slightly possible. There isn't any pressure on those, only vacuum. That's why they aren't fastened tighter. Your most likely cause for that failure is a problem with that carb not delivering enough fuel which carries the oil to lubricate the cylinder. There's probably a restriction in the main jet. Take it apart. If there is any varnish in there, you'll need to rebuild all of them including those on your other motor. If there's varnish in one, it'll be in all. Other factors could've taken that cylinder out, but I'd start by looking at that carb.

 

[Crackerasscracker]

Re: 1999 Carb Merc 125 SWS

Willy B, If the carb was clogged, would it have run at high cruise for two hours without incident before all of a sudden blowing? Should I have gotten an overheat alarm? I had recently changed the water separators and I regularly use fuel treatment. I also got a tune up this summer. (less than 50 hours of running) I guess I was wrong about the tube, but there was oil all over the inside of the engine and that tube was off of the connection to the cyl... Could it have been loose for a while and allowed water into the cyl? It still seems like there should have been better design on that whole part of the system.....

 

[Crackerasscracker]

Re: 1999 Carb Merc 125 SWS

Originally posted by Crackerasscracker:<br /> Willy B, If the carb was clogged, would it have run at high cruise for two hours without incident before all of a sudden blowing? Should I have gotten an overheat alarm? I had recently changed the water separators and I regularly use fuel treatment. I also got a tune up this summer. (less than 50 hours of running) I guess I was wrong about the tube, but there was oil all over the inside of the engine and that tube was off of the connection to the cyl... Could it have been loose for a while and allowed water into the cyl? It still seems like there should have been better design on that whole part of the system.....

Seriously... anyone know the answer here?