Running on 5 cylinders......

[Canlab]

I was running at WOT on my 2004 Challenger (240 EFI) when it died. When I restarted it, it made some ugly noises then quieted down and seemed fine. I used it for a bit and it had good power, planed easily and cruised nicely at 35 mph. It also restarted at the turn of a key. The next morning the starter sounded different but it started easily and ran good. I didn't like the sound of the starter so I pulled the plugs and did a compression test. Unfortunately one cylinder shows no compression and the plug was fried.

Can that one cylinder just be fixed or do I need a complete rebuild. The problem is that around here the boat is virtually worthless, so I don't want to sink a bunch of money into it. Plus I'm thinking of getting a new boat next year. As for running on 5 cylinders, could I reliably do that for awhile until I buy a different boat? If I did would that mean raw fuel and oil would be spitting out the exhaust into the lake from that one cylinder?

It was shocking how well it was starting and running on 5 cylinders. Had it not been for the starter sounding different, I would have never noticed.....

 

[Dr Honda]

Can it run on 5 cyl's?? sure it can.

Can you continue to run it as is?? NO !!!!!!!!!!!!


Basically, with the busted parts still moving around... eventually, it will disintegrate. AND, could cause larger issues. If you removed that piston, rod, and disconnect the injector on that cyl... it would probably run just fine. That is... until the rest of the engine fails. Chances are, if one cyl gave up... the rest isn't far.


BUT... you are in a good position. You know it's heading to a total failure, but it hasn't yet. SO... pull the engine, and do a basic rebuild. Hone the Cyl walls, replace the pistons, and bearings. If you do the labor, it's going to be less than $1500.


With a freshly rebuilt engine, the boat is worth good $$ when you go to sell it. With a blown engine... it isn't worth much.

 

[nataliator]

Consider yourself lucky that it failed and you caught it before it turned into a grenade for the cases!

 

[Sportster-2001-951C-Stock]

I must ask, do you also drive your car with the pedal constantly to the metal?

 

[Canlab]

I must ask, do you also drive your car with the pedal constantly to the metal?

No, what happened is we had one of those very rare days when the lake was smooth as glass. I have virtually never had this thing at top speed before so I tried it. It all happened pretty much within 30 seconds of being opened up. I'm not sure if the engine overheated or what but there was no warning. I regret doing it now and if I get it fixed will never do it again.

 

[Canlab]

Can it run on 5 cyl's?? sure it can.

Can you continue to run it as is?? NO !!!!!!!!!!!!


Basically, with the busted parts still moving around... eventually, it will disintegrate. AND, could cause larger issues. If you removed that piston, rod, and disconnect the injector on that cyl... it would probably run just fine. That is... until the rest of the engine fails. Chances are, if one cyl gave up... the rest isn't far.


BUT... you are in a good position. You know it's heading to a total failure, but it hasn't yet. SO... pull the engine, and do a basic rebuild. Hone the Cyl walls, replace the pistons, and bearings. If you do the labor, it's going to be less than $1500.


With a freshly rebuilt engine, the boat is worth good $$ when you go to sell it. With a blown engine... it isn't worth much.

Thanks! I don't have the tools, knowledge or facilities so I'm going to check around to see what it would cost to rebuild. Reasonably ballpark what should it cost to rebuild this engine?

 

[Dr Honda]

Shops are expensive, and most won't "Rebuild". They just want to replace. SO... $5k to $7k USD is normal.

 

[Sportster-2001-951C-Stock]

It all happened pretty much within 30 seconds of being opened up. I'm not sure if the engine overheated or what but there was no warning. I regret doing it now and if I get it fixed will never do it again.

A WOT session will reveal weaknesses, however, this engine must've already been hurt previously or had an undetected problem. These are tough motors and a few minutes of WOT doesn't qualify as excessive.

Some people do run them full throttle for long distances and that always makes me cringe a little b/c I see more boat engines broken than worn out.

I'll agree with the others at this point, if you continue running this engine the damage will only become more expensive if it doesn't fail right away, which it probably will based on one piston is roasted (no compression).

Look for the root cause.

During repair the root cause needs to be resolved or the repaired engine will suffer the same fate. Look for something like a clogged fuel injector, or maybe ignition timing too far advanced (misadjusted), even having the incorrect spark plugs (range too hot) could be the cause. I'm sure there was a reason besides just the short WOT session.

 

[Canlab]

Shops are expensive, and most won't "Rebuild". They just want to replace. SO... $5k to $7k USD is normal.

You are right on the money. I went to two marine repair shops. They both were very knowledgeable and seemed to have experience with these engines as both asked me if it was one of the bottom cylinders that failed. One actually showed me the same engine with a blown piston he had sitting around.

Both quoted between $3k to $7k depending on the damage.

Two questions: 1.) Where are some good places to buy a reman. engine or engine block if need be? 2.) Have you ever heard of anyone dropping in a 4-stroke powerhead as a replacement?