T-stat Seal

[Mumbles]

I know which way I always install the seal on the OMC thermostats but which is the factory correct way? The reason I’m asking is because I get so many motors with it installed both ways. Is it as in the first photo or the second photo? Some motors seem to like it either way.

• This topic was modified 4 years, 6 months ago by Mumbles.
• This topic was modified 4 years, 6 months ago by Mumbles.

[fleetwin]

Well, the prescribed installation is with the rubber sleeve pointing downwards as shown in your second picture. I always figured having the sleeve pointing downwards helped center the thermostat in its pocket and keep the dissimilar metals from rubbing on each other…

[frankr]

Agreed, skirt points downward. As for a reason, I dunno, but will accept fleetwin’s as good as any.

[Mumbles]

Hmmmm…… I posted this same question on the clubs Facebook page and they all said it goes the other way. 😵

[billw]

I’m pretty sure I have seen unmolested engines from the factory that have had it facing up but I always put them down because it just makes more sense and looks better to me.

Long live American manufacturing!

[fleetwin]

Well, I am confident OMC has always prescribed that the rubber seal sleeve faces downward toward the driveshaft or inward toward the crankshaft on engines with horizontally mounted thermostats. That being said, it probably won’t make much difference either way, unless having the rubber lip facing upwards/outwards somehow affects water flow on some engines.

I am not on Facebook, but would love to hear from anyone who insists the rubber lip faces upwards/outwards, or if anyone has actually seen this in print from an actual OMC manual/bulletin…

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