Force 50 Foam in the Reeds

[chris.olson]

I had a 507F5A come in late this afternoon on a pontoon that had quit. The foam insulation inside the cover deteriorated, fell down and got shredded by the flywheel. That stuff ended up getting sucked in the carb and into the reeds. The reeds were literally packed with it.

I would recommend that anybody running these engines that don't have any screens or silencer on the carb check that foam. If it's bad, just rip it all out of there to prevent headaches. It doesn't do much to quiet the engine down anyway.

 

[jerryjerry05]

This foam has KILLED many a Chrysler/Force.
Most don't find it until it's too late!

 

[chris.olson]

In this case, being on a pontoon, it is rarely run at full throttle. It appears that most of it got packed into the reeds, which caused them to quit sealing. I pulled the powerhead, and since I'm not sure how much grit got into the lower end I'm going to rinse the engine out with diesel fuel and hopefully it will run again.

But yes, certainly, that stuff can completely DESTROY your engine. The foam collects dirt with age and the grit in it is what will chew up the powerhead. Doesn't look like it was a slow failure. The glue let go and it got into the flywheel and probably happened all in one day.

 

[chris.olson]

Unfortunately, this engine required a partial overhaul of the powerhead. I decided to take a look at the rod big end bearings and there was some galling visible from the rollers skidding. Main bearings, pistons and cylinders were fine.

I polished the crank, filed the rod caps and rigid-honed the rod big ends, scuffed the cylinders and relieved the ports (I was not happy with the job the factory did on the ports), re-assembled with new rod bearings (Mercury Marine part #31-8M0045428 bearings fit this engine), old pistons and rings and it runs again.

Just a warning to folks - GET RID of that foam insulation in your engine cover BEFORE it wreaks havoc.

 

[topgun3690]

Totally agree with removing the insulating foam in the cowling. Did it years ago when it started deteriorating. Not much difference in sound either.