Spare carb needed

I've been noticing several posts where lucky members have come into bonanza of older motors. It would be wonderful if youse might share the love. I've got a 1987 Johnson 15 and would love to score a backup carb for the day that the inevitable happens. These older carbs are like hens teeth to get hold of.

Everyone wants the 15 hp carb so they can convert their 9.9 up engines to a 15..lots of extra 9.9 carbs out there !!

blufrog1 said:

I've been noticing several posts where lucky members have come into bonanza of older motors. It would be wonderful if youse might share the love. I've got a 1987 Johnson 15 and would love to score a backup carb for the day that the inevitable happens. These older carbs are like hens teeth to get hold of.

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Wonder if a 9.9 carb would work on a 15?

blufrog1 said:

Wonder if a 9.9 carb would work on a 15?

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Yes. It would detune it. Watch the plugs to make sure it's not running lean.

Why would anyone need a spare carb? They don't really wear out, you just have to take it off and clean it once in awhile. If anything, you may want to buy a kit. You buy a used carb it'll likely need cleaning and maybe a kit anyway.

As for 9.9 to 15 conversions, does anyone actually do that? Or at least do it these days? I looked for a 15 HP carb for awhile for a 9.9 I got and the damned things were going for as much as an entire motor would.

LaqueRatt said:

Why would anyone need a spare carb? They don't really wear out, you just have to take it off and clean it once in awhile. If anything, you may want to buy a kit. You buy a used carb it'll likely need cleaning and maybe a kit anyway.

As for 9.9 to 15 conversions, does anyone actually do . Thethat? Or at least do it these days? I looked for a 15 HP carb for awhile for a 9.9 I got and the damned things were going for as much as an entire motor would.

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Actually in 87 there were three versions of the 15 hp carb in use. The latest versions had a problematic plastic top plate while earlier versions had a metal plate. The plastic top is quite expensive and much more troublesome. My engine spent 4 months in the repair shop last year. First it wouldn't run wot, then it wouldn't idle. After many hours, new fuel pumps (2), new fuel lines, 3 head gaskets, two carb kits and numerous needle seats, reed valve cleaning, head conditioning and nw plugs the shop returned it without charging me because it won't idle. I'm thinking a different carb might put it right but who knows???

Sounds like a lemon my friend. Think I'd replace it with a rock solid OMC circa 60s-70s. You can pick one up to for the price of a carb I'll bet. Why worry about spare carbs when you can have a spare motor? I do see your point though. Sounds like a fragile set up.

Did they vacuum test the block? Two strokes with bad seals won't idle consistently, won't stay adjusted worth a poot (can't get idle and high speed), and usually run hot. New carb won't fix that.

beagle said:

Did they vacuum test the block? Two strokes with bad seals won't idle consistently, won't stay adjusted worth a poot (can't get idle and high speed), and usually run hot. New carb won't fix that.

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I can't say if they did that. How would I go about that myself?