Thrown rod

[superfly42]

I purchased an '02 Challenger 1800 about a month ago (Merc 240 EFI). The motor ran great. No smoke, even on cold start, idle was great, and it ran smooth at speed as well.

I took this out for the 5th time, was up on step (around 4500 RPM) and I heard a rattle but no power loss. I initially thought I had pulled rocks up into the jet - that was what it sounded like. I initially troubleshoot the jet, but everything was clear. So I opened the engine compartment and could tell it was coming from there.I inspected everything I could see, and nothing was loose. Fan belt good, nothing loose.

I thought about the fact that the noise was coming from internal, but reasoned that I would have had power loss and convinced myself there was something loose external I just wasn't seeing. Unfortunately, I re-started the motor - and that is when it happened. The motor seized and there was no life. I looked down in the compartment and there were bits of the block and a shaft sticking out of one side.

Two questions:

1) What did I do?!? Is this a freak catastrophic failure or did I cause this? I normally operate the boat ~4000-4500 RPM when at speed. I rarely go above 4500 and when I do it's short lived. A thrown rod is usually because of high rev'ing and abuse to the the engine, which I don't do. Oil reservoir had plenty of oil. No overheating issues. I just don't get it.

2) What next?!? I think a refurb/reman will be too expensive and I'm not willing to spend the time to do it myself (mostly because I'm not a good mechanic, and it'll be a bigger waste of $$).

I'm hoping that maybe this group might know something that I don't. I've already shopped around on Crowleys and eBay, and I'll be reaching out to local shops too. Should I just part this out and cut my losses?

 

[nataliator]

When's the last time the oil pump was serviced?

If the motor wasn't getting oil, it doesn't matter how gently you were running it - 4000 RPM is plenty to blow it up.

 

[Ckrawiec]

Sounds like a thrown rod right through the case...been there, done that to a Kawasaki ski, piston arm punched right through the bottom of the case (which in my case was not that bad actually).

I pulled the engine, disassembled it, had the lower aluminum case TIG welded back together (on a fixture to keep it from warping), hole and all, ground out any excess metal to allow the crankshaft to spin freely, rebuilt the engine guts and put it back into service. The ski ran fine again AFTER all that BUT the cost and time when I was all said and done was pretty much what I could have purchased a completely re-built engine from the get go (but I learned a lot along the way).

BTW: The failure was a bad oil pump...unbeknownst to me until it STB.

If you decide to keep the boat...replace the engine with a rebuilt...save the time OR "part it out". No matter what...the boat is toast for the time being....sorry for your pain!

 

[dblackstone]

on that motor the culprit is probably the oil pump

DR Honda has a very detailed post on his rebuild. Search posts and you will find info on where the best place is to get a rebuilt motor

 

[superfly42]

After trolling around the forums, I'm convinced the issue is the oil pump. One thing is for sure, I'll never trust an auto mixer again. Ever. Manual mixing is just too easy to justify the risk.

This forums has been an awesome resource!

I spent about 8hrs of my life researching an electric conversion . I spec'd out a motor, controller, cooling, gauges, and then was quickly reminded of the insane cost of batteries. How nice would that have been though?!? (except range anxiety!)

Back to reality - Thanks to this forum, I've found a remanufactured powerhead at a price I'm willing pay (seilermarine.com).

I'm going to keep looking locally just in case I can find a donor from a salvage yard that has good readings.

I still haven't decided if I'm going to go this route or part it out.