Permatex for Power-head base gasket? (304314)

[LARRY CATON]

I searched the threads about the power-head base gaskets, but didn’t see anything about foregoing the gasket and using some type of “Form-A-Gasket” such as the original Permatex #2 (non-hardening), or the newer Permatex Optimum series designed for easy disassembly.

I just replaced the water pump impeller in a 5.5 Hp, Johnson CD-15.  Prior to removing the power-head, I noted that the gasket is about 1/16″ thick.  I’m wondering if the gasket provides a critical clearance.  The drive shaft seal is essentially “spring loaded” with the spring beneath the carbon seal, O-ring, etc., so I’m wondering why I haven’t seen anyone mention using Form-A-Gasket.

I understand that you wouldn’t want to over-apply a gasket-maker that could squeeze out, break away, and cause a cooling system clog.

1956 Johnson 15 Hp, FD-10
1957 Johnson 5.5 Hp, CD-14
1958 Johnson 5.5 Hp, CD-15

[Bob Wight]

I’ve not heard of using any type of form-a-gasket sealer in place of the gasket itself.  If you were concerned about easy disassembly in the future, some folks just apply grease to the base gasket – it will act as a gasket sealer while allowing disassembly in the future.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20
1982 Evinrude 25hp

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[JACQUES]

the PH  base gaskets only seals  exhaust and water no big PSI like  cyl head etc..

 

I have never applied sealant

Joining AOMCI has priviledges 🙂

[Don]

Use the proper base gasket, skip the goop

[JACQUES]

18-3001B is for the 55  5.5hp… carefull base patterns differ

Johnson Evinrude outboard impellers, seals, lower unit kits, water pump kits, gaskets – VintageOutboard.com

Joining AOMCI has priviledges 🙂

[LARRY CATON]

I’ve never heard of eliminating the PH gasket either.  As Jacques points out, it’s a “low pressure” joint that blocks exhaust and water, and some people apply grease to make future disassembly easier.  I’ve heard that greasing the gasket allows you to use it at least twice when doing maintenance.

I’m just wondering if there are any CONS to using Permatex?  I’ve got plenty on hand, whereas I’ll either have to order a $20 gasket or trace one onto gasket sheets I’ve got.

 

1956 Johnson 15 Hp, FD-10
1957 Johnson 5.5 Hp, CD-14
1958 Johnson 5.5 Hp, CD-15

[wedgie]

LARRY CATON wrote:

I’ve never heard of eliminating the PH gasket either.  As Jacques points out, it’s a “low pressure” joint that blocks exhaust and water, and some people apply grease to make future disassembly easier.  I’ve heard that greasing the gasket allows you to use it at least twice when doing maintenance.

I’m just wondering if there are any CONS to using Permatex?  I’ve got plenty on hand, whereas I’ll either have to order a $20 gasket or trace one onto gasket sheets I’ve got.

 

Not an ideal solution, but I say go for it. I’d be interested in your results. maybe cut a shim the same thickness as an original gasket and use as spacer gauge When bolting down the powerhead. Get the gap close, then let cure for 24 hours and snug bolts down a bit more to compress the silicone.

[Sam M.]

Check the clearances first.  You could put the powerhead on without any gasket but with every applicable spring and seal on the driveshaft, without bolting the powerhead down.  Make sure it is sitting on the bare mating surface without any gaps.  Then analyze the vertical play in the crankshaft.  If there still is as much as there was with the powerhead off, it could work.  If the vertical play goes away, by installing an insignificantly thick layer of liquid gasket, you would have your driveshaft pushing on your crankshaft and I think that would be bad for the non-thrust bearings which are meant to withstand pressure in the other direction.

[Don]

I can understand using the goop in an emergency, or in a case where gaskets were unavailable.  But why chance making a mess, possible leaks, or plugging passages needlessly.

[Author]

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