what happens when a mechanic rushes…

[johnyrude200]

Might be a good thread for folks to share some comical stories.

So FRANK, this is the 2ND 9.5hp where the inner exhaust gasket was faulty in this exact spot I’ve seen this year. Both, fortunately, have been fresh water motors and all fasteners came loose with little effort. The first one, it was a clear gasket failure due to age. This one, not so much. It was pretty obvious someone else has been in here, and the gasket is ‘fairly’ new (within the last 10-15 years). Wrong screws holding things together (hardware substitutes…that were all rusty, fortunately still holding together though).

HOWEVER, they did a HACK job, rushed, and installed it incorrectly.

Quick summary – this motor was destined for the scrap pile, I basically replaced every perishable aspect but the powerhead and gearcase were mechanically OK (4 L.U. seals replaced, gears OK, powerhead good compression, cosmetically spent but intact, ignition and fuel systems not present at time of acquisition).

After I spent 4 hours fixing everything I expected, I looked forward to putting some gas to her and she started on the 3rd pull as these should when dry, then within 6-7 seconds there were running problems. Missing, running erratically on 2 then 1 then 2 cylinders. I shut her down, pull the plugs, and it’s obvious there is water intrusion.

Pulled the head to discover a new head gasket…so only one other area to inspect (exhaust bypass cover)…and oh what joy it is to attack that on the 9.5’s.

Question for T2, fleet, pap, mumbles…why place the lower cylinder head screw so close to the water bypass passage? That’s always the one that is a royal PIA to grab ahold of with any sort of wrench/socket. Forget about it if it’s a moused or salt motor. Labor of love at that point.

Here’s what the normal usage bypass cover looks like, before super heated water comes by and cleans those passages out. Pulled apart one of my parts motors for example purposes.

[1946zephyr]

Yea, I’ve had some interesting experiences with that particular area of a motor. I picked up a 1957 Evinrude Fleetwin that drove the mechanics nuts. They went through the motor and surfaced the head and everything. It turned out, that the inner plate had a pin hole in it and water was spraying into the lower exhaust port at high RPM’s. I made a new plate and the problem was solved. That incident was what led me to make the stainless inner exhaust plates for those models.

[johnyrude200]

water intrusion happens, randomly, but happens. But working on a variety of these smaller OMC motors it seems that each HP family of motors has it’s own nuances of failures.

Wondering if this is the unpredictable failure point of design where the water and exhaust systems intersect and trend in failure.

[fleetwin]

I guess I would glue the new gasket in place with type M/847, looks like a flawed design, needs a few more fasteners to clamp that gasket in place.

[dan-in-tn]

That looks like the newer style gasket with adhesive added. It is suppose to be installed dry. I would be more worried that the parts were not flat or someone did not torque the fastners properly. Yes it would be nice to have more fastners in and around the area, but you don’t have that luxury. Not sure additional adhesive is going to help. Those prepped gaskets are kinda funny and become slick when you try to add more glue to them. Parts need to be clean, dry and straight for proper compression. If they have held for this many years something most have been right!
JohnnyRude200 as far as your comment about where they put a particular fastner? You can bet an engineer will put a screw/bolt where it will be the hardest to get at as to its value to the assembly. Engineers work on motors while they are just blocks or powerheads, rarely as complete engines. That is someone else’s job to figure out how to service the creature they create! Some of the fixes they are forced to come up with for their original designs are referred to as band aids.

Dan in TN

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