1950's Johnson breathing problems?

[55Crestliner]

I've been doing a little work on my '57 Johnson 18 horse the last couple days, and I got to thinking (I know, bad thing). How in the world does this motor get air to the carb? The hood is so well sealed up, with a gasket at the bottom, gasket for the face plate, and a plate where the pull cord comes out. Seems to me that the motor would starve for air.I know I can answer my question by taking the hood off next time I go out, see if RPM's go up, but I was curious if some of the more experienced ones here can tell me about this. Did they take the hoods off for racing? Make an air inlet? Didn't bother? Do tell. 55 "always after more speed" Crestliner.

[DJ]

The air comes in through openings at the base of the cowl, just above the clamp bracket.If your engine runs better, with the cowl off, you have an exhaust leak. Probably from the engine exhaust cover, or the powerhead base gasket.

[55Crestliner]

Well, that's kinda my point, there are no openings in the base of the cowl. None. Motor is running good, acually great, I'm just always wanting more.

[DJ]

55,You'd be surpised at how much air can come through very small openings.As far as wanting more. More air won't help. Those engines were designed that way. Allowing more will only result is lean running conditions and piston melt down.If you want a "race" engine, there's more to it than allowing more air.

[Chinewalker]

Those "seals" are to keep sound in, not air out. They do a fair job of it on the sound end (listen to a '54 Evinrude 15 that lacks the silent treatment vs. a '55 with it!), but it is far from air tight. Take your cowling off, flip it over and try filling it with water. It'll leak like a seive...- Scott