Johnson QD-16 base gasket

[Steve Martin]

I’m assembling a QD-16 10hp. The parts manual powerhead group shows a 303892 base gasket and the driveshaft casing group shows a 377070 gasket at the upper surface.  That would seem to indicate they would be stacked on top of each other which makes no sense to me.  Can anyone shed some light on this?

[aquasonic]

I don’t know about the 1955 QD-16, but the 1954 QD-15 actually has two separate base gaskets for the powerhead. I’m certain that someone with experience with the QD-16 will be able to answer this question. Fleetwin will know this.

[frankr]

377070 is a gasket and baffle kit with a stainless steel baffle and 2 thin gaskets which replace the original gasket.  The idea is to keep the exhaust away from the lower crankshaft seal.  Good idea I suppose but doubtful that it did much good.

[Steve Martin]

Thanks Frank. I’m unclear why both part numbers are shown for the same application on the two drawings.

[frankr]

Unclear for sure. I can’t see your parts book, but I’m surprised that 377070 gasket and baffle kit appears on a 1955 QD-i6 parts book, or for that matter, even compatible with the 10 hp.  That mod came about in later years in response to powerhead failures on the 15 hp due to crankshaft seal failures.

[Steve Martin]

Actually it shows a gasket only with part number 377070 –  no plate and second gasket.  Confusing.

[Steve D]

I was confused by that too…

[Mumbles]

303892 supercedes to the current P/N, 304588.

I can’t find anything for 377070.

[Steve D]

Shows just a gasket in the manual but actually a baffle and gasket kit as Frank mentioned. Edit: A ’56 manual I just checked shows 303892 on the power head group page and exhaust housing group page but no baffle.

 

[Steve Martin]

So what’s the consensus on the correct part(s) for the QD-16?

[Author]

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