Watermota Sea Panther Seizure!

[ncritchley]

That's the engine, not me. My Sea Panther was quietly ticking over when it suddenly stopped. There was no bang or untoward noise at all. Plenty of fuel and cooling water and no smoke or steam. On checking though it has seized almost completely, with about 1/8 of a turn of the crankshaft still possible before it comes to a stop with a metallic clunk. I've stripped it down as far as removing the head, with no sign of any problem. The piston tops look good, as do the valves and injectors. I've removed the chain case, and the timing and water cooling chains are intact and seem fine. So at this point I'm going to lift the engine out. I guess that if I remove the sump and get access to the bottom end I'll definitely see what the issue is? Does anyone have any thoughts or suggestions, perhaps from a similar experience?
Thanks to all, Neil

 

[penfold]

Do the pistons move when the crank is turned the 1/8th? It's a 40+yr old engine, it's had a good innings.

 

[ncritchley]

Yes they do. The pistons and the bores look good. Unless it's a broken pin or conrod ( and how? the thing was at tickover...), I'm wondering if it's something at the rear i.e. drive end of the engine, perhaps to do with the ring gear. Anyway it's coming out next week, so hopefully all will be revealed! Thanks for your interest.

 

[burgundyben]

Have you taken the starter motor off?

 

[ncritchley]

Yep, and the fuel pump. The only thing still attached is the injector pump. The gearbox s in neutral and rotates freely.

 

[Boater Sam]

Drive plate collapsed?

 

[bikedaft]

Tickover, maybe oil pressure was too low for one of the oil ways, or partially blocked etc?

 

[WoodyP]

Good luck. If you get it going again the engine can have a new name. Lazarus.
I ended up replacing with a Beta 1050. Expensive .
I expect you already know that Stephenson Marine are the only supplier of parts, but they do have a useful repair manual. Stephenson Marine, Noss on dart Marina, Bridge road, Kingswear, Dartmouth.

 

[jwfrary]

Rocker cover off to check for a dropped valve

 

[footsoldier]

I've stripped it down as far as removing the head, with no sign of any problem. The piston tops look good, as do the valves and injectors.

 

[Boater Sam]

Get down to the flywheel.

 

[ncritchley]

Thanks everyone for your kind sugegstions. I'll post right back when I get to the bottom of it!

 

[Bodach na mara]

Best of luck Neil. I had a Sea Panther for 19 years with no trouble at all. It broke down the year after I sold the boat.

Not that engine but the only time I have had an engine seize solid like that was with a Clinton outboard. When it was stripped down the problem was found to be a needle roller that had managed to get into the bore and jam the piston. As far as I know there are no needle roller bearings in your engine but I am reminded of a seized Captain in another boat that turned out to be a gearbox problem with a broken bearing.

I'm following this thread with interest.

 

[ncritchley]

Drive plate collapsed?

Interesting. I'll definitely investigate that.

 

[ncritchley]

Hi everyone. Well, I now have the answer, at least in part. I lifted out the engine yesterday and removed the sump cover, but everything still looked perfect. So I removed the CAV fuel injection pump.... and of course the engine freed up instantly! So somehow the injection pump has seized. How? I've always treated these things as sealed units best investigated by experts, so I'll either send it off for repair or look for a straight replacement. But actually I'm relieved that I won't have to dismantle the whole bottom end. Thanks to everyone for your kind interest.

 

[Boater Sam]

Hi everyone. Well, I now have the answer, at least in part. I lifted out the engine yesterday and removed the sump cover, but everything still looked perfect. So I removed the CAV fuel injection pump.... and of course the engine freed up instantly! So somehow the injection pump has seized. How? I've always treated these things as sealed units best investigated by experts, so I'll either send it off for repair or look for a straight replacement. But actually I'm relieved that I won't have to dismantle the whole bottom end. Thanks to everyone for your kind interest.

Unusual for an injection pump to lock up, is the drive still OK, nothing twisted or broken? Better than a bottom end job.

 

[ncritchley]

Unusual for an injection pump to lock up, is the drive still OK, nothing twisted or broken? Better than a bottom end job.

Everything seems good, insofar as my limited expertise allows me to judge, other than something that's jammed in the internals of the pump. An unusual case for sure. I don't think I feel up to repairing it myself, and I do wonder what damage has been done to the pump, given that the jam was enough to stop a running engine. That's a lot of load!

 

[Boater Sam]

Everything seems good, insofar as my limited expertise allows me to judge, other than something that's jammed in the internals of the pump. An unusual case for sure. I don't think I feel up to repairing it myself, and I do wonder what damage has been done to the pump, given that the jam was enough to stop a running engine. That's a lot of load!

That is why I asked about the drive. Is it geared or chain? I don't know these engines.

 

[ncritchley]

That is why I asked about the drive. Is it geared or chain? I don't know these engines.

Chain driven from a sprocket on the crankshaft to a sprocket with a splined shaft that drives the pump. On just a visual inspection, and turning the engine over by hand, I'd say that things look alright, no broken splines or teeth. But I'll need to have a better look next time I'm there.
In the attached drawing the pump sits in the round hole in the casting on the far right.

 

[Boater Sam]

I knew they were complicated, never appreciated how so. No chain tensioner? At least its a duplex!
Should be no problem getting a CAV pump sorted.
Have you a local diesel centre, I don't know your location?