Carb base gasket buttered or no?

[liquidlew]

Hey, transferring my 2bbl mercarb to a different manifold, do I use sealer on the new gasket or no? The old one is stuck to the manifold pretty good and I scraped what looks like sealer residue off the bottom of the carb.

 

[Maclin]

Re: Carb base gasket buttered or no?

I always install them dry. If they are truly base gaskets then they will usually come off intact. It is when somebody glues them down that problems start.

 

[liquidlew]

Re: Carb base gasket buttered or no?

Thanks Maclin, I didn't think it needs sealer but it don't hurt to ask. The old gasket is probably just stuck (on the manifold) from being on there for almost 20 years, by the looks of it, it's never been taken off, and I've had the carb rebuilt by a shop, you'd think they would've put on a new one? Well, as the old saying goes, if you want something done right...you gotta ask the pros on iboats, get a factory manual, and buy OEM parts!

 

[JustJason]

Re: Carb base gasket buttered or no?

personally i'd use sealer. The sealing surface of the intake will inevitably develop nicks and pores.
use sealer... but use it lightly.

 

[liquidlew]

Re: Carb base gasket buttered or no?

That makes sense to me too, I would avoid it if you all said absolutely no, but, just a light thin coat might make me sleep better at nite. Now what's the right stuff to use? Perfect seal or silicone? Thanks!

 

[Maclin]

Re: Carb base gasket buttered or no?

If you are using a true 3/8" thick carb base gasket with reinforcement spacers in the mounting holes just leave it dry. The materials are designed to crush around the facings, no sealer needed.

 

[Windykid]

Re: Carb base gasket buttered or no?

Dry! Not to mention fuel tends to eat through most sealers.

 

[liquidlew]

Re: Carb base gasket buttered or no?

Yeah, the new gasket is Quiksilver and its really thick compared to the original one which is almost paper thin. Reonforced spacers in the mounting holes? Is that something extra or is it built into the gasket? Also, the new gasket is just a big square opening, old one has 2 round cutouts, any problems with that?

 

[JustJason]

Re: Carb base gasket buttered or no?

Just got in from my morning job. 130 yamaha outboard won't idle.
Verdict....
Carb base gaskets leaking
Removed carbs... cleaned all the mating surfaces... cleaned the gaskets.... applied a thin amount of OMC type M sealer...
Problem solved... runs/idles fantastic now

 

[Maclin]

Re: Carb base gasket buttered or no?

There should be metal sleeves or collets or whatever you want to call them in the bolt holes. They keep you from tightening down too much and breaking off an ear from the carb's mounting plate.

No sealer, this is an automotive based I/O setup.

I have no expertise in what the service recommendations are for a Yamaha outboard with vertical mounted variable venturi carbs, but I am pretty sure whatever it is has no bearing on this application.

 

[Maclin]

Re: Carb base gasket buttered or no?

The open hole will work fine. It sounds like prior to this there was no proper base gasket on yours. The base gasket provides some heat insulating as well as sealing imperfections in the castings, that is why it is that thick and made out of the stuff it is made from.

I like to match the intake's configuration as far as the base gasket, but there is no measureable detriment to using the open hole base gasket over a two or 4 hole intake.