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Good on getting it running. Yes to sea foam. Before I would go to the work of tearing into the carbbi would get the gas tank empty and put some lacquer thinner in. Pull out the drain screw again and let it drain thru the carb. Get as much of the lacquer thinner out of the system, fill with fresh gas and give it a go. I would not use very much lacquer thinner. Maybe a cup?
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Running a motor partially choked is running it in a "lean" condition. Running a motor in a lean, inefficient condition causes overheating of the piston. An overheated piston can suffer from a hole blown through it. A hole blown through a piston causes you to have to rebuild the motor.
Get the carb fixed.
If you run seafoam through it, don't do it partially choked. Do it with a full open throttle.
I'm a fan of seafoam, I use it twice a year. First and last run of the season in all my small motors including the outboard. I have no idea how or if it really works but I'm still running small motors from the 80's and they run fine. I still use Stabil for storage and I don't run carbs dry. It's my feeling that a dry carb is fine if everything is fine to start with but if there's any goo in the carb, it will harden and lock up the float and/or needle valve if run dry.
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(12-31-2016, 04:31 PM)bennybmn Wrote: The other night I went out there and whacked the carb bowl with a screwdriver handle a few times and pulled out the little drain screw. Fuel flowed so I figured the bowl was unstuck.
BOOM!
+5 on running seafoam through it now that it is running. Make sure you run some stabil through it before you shut it down for the season.
Mark
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Put seafom in it the other day, coincidentally. I also picked up some new Stabil. Haven't had a chance to run it again since. I plan on super-stabilizing some gas and filling up my mower too. I do happen to have some fuel line and a filter that I was going to put on the mower...
On the choke issue... The Brits (my Triumph shop manual anyway) refer to the choke as the "enricher" which leads me to believe it's choking the air, not the fuel. In fact I think, at least with the Kehin carbs on my Bonneville, it's almost like a bypass/additional fuel circuit, which is why it runs with a little choke even if the main jet is clogged. Other than the use of the word "enricher", most of this is internet based conjecture from years on the triumph forums, and frankly I haven't been very active there the last few years, so it's old conjecture at that. But if anyone could comment on the actual function of the choke...
Benny
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More fuel, less air.
Mark
I'm no expert, unlike everybody else here - Busdrver
Nah...I like you, young feller...You remind me of my son... Timberwolf 03/27/12
Here's a fact: Benghazi is a Pub Legend... CharlieD 04/19/15
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(01-03-2017, 11:10 AM)CLETUS Wrote: More fuel, less air.
Love your economy with words.....
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Kehin
(01-03-2017, 09:36 AM)bennybmn Wrote: Put seafom in it the other day, coincidentally. I also picked up some new Stabil. Haven't had a chance to run it again since. I plan on super-stabilizing some gas and filling up my mower too. I do happen to have some fuel line and a filter that I was going to put on the mower...
On the choke issue... The Brits (my Triumph shop manual anyway) refer to the choke as the "enricher" which leads me to believe it's choking the air, not the fuel. In fact I think, at least with the Kehin carbs on my Bonneville, it's almost like a bypass/additional fuel circuit, which is why it runs with a little choke even if the main jet is clogged. Other than the use of the word "enricher", most of this is internet based conjecture from years on the triumph forums, and frankly I haven't been very active there the last few years, so it's old conjecture at that. But if anyone could comment on the actual function of the choke...
The Kehin carbs are typical older technology European style piston carbs. Like SUs or Strombergs. They aren't generally high performance but if you know how to set them up and balance them, they're very reliable. Those were the first carbs I learned to work on being an old Datsun head. The Brits actually made good carbs (amazing as that seems), Americans just didn't know how to work on them. American downdraft carbs reacted much faster to the gas peddle but fell out of adjustment easier.
When you have a fuel problem like a clogged or stuck needle valve, you aren't getting enough fuel and are getting too much air for that amount of fuel. When you "choke" it, you are closing the butterfly valve in the air-intake throat of the carb and choking off the air making the balance of fuel to air "richer". There isn't really more fuel, there's just more of it compared to the mount of air.
When starting a motor, there's already cold air in a cold piston cylinder and the droplets of fuel from the carb's jet don't atomize and they stick to the walls of the cylinder (condensate) and have a hard time igniting. There's basically too much air and not enough fuel at that moment. The fuel is "wet" and too much "wet" fuel will quickly flood the cylinder. Choking the intake forces a proportionately greater amount (fuel to air) of fuel into the cylinder all at once so the engine fires. It gets hot enough in a few seconds to keep the fuel vaporized and be able to run without the choke closed.
I see a lot of posts in outboard forums about "my engine only runs with the choke on". That means the motor is starved for fuel. Either the float is stuck, there's a clogged filter, the needle valve is clogged or stuck or fuel lines are collapsed or gooped up from degradation, probably caused by ethanol. Ethanol is causing a lot of these problems by dissolving fuel lines and that crab is sent down the line, into the carb bowls and it tries to get through the needle valve. When it is inside the carb bowl it turns to jelly and prevents things from moving freely. That's why I don't run my carbs dry. That stuff won't always drain out with the fuel. It dries out in the carb and turns into glue.
I have (had) clear green OEM fuel hoses on my outboard and it was running rough on start up. By pulling plug wires, I was able to tell which cylinder wasn't working. I pulled that carb apart and it had a bunch of green goo in it. I'm sure it was caused by ethanol eating the vinyl fuel hoses. I cleaned it up and it ran fine.
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01-04-2017, 09:49 AM
(This post was last modified: 01-04-2017, 09:50 AM by bennybmn.)
I see what you're saying about the butterfly... I can see that happening on my lawnmower, but that's as easy as popping the filter off! It runs fine, and very smoothly with a little choke. So I get it that the choke is evening out the mixture, but it's still managing to pull enough total mixture in order to run. Seems fishy to me... see what I mean?
Edit: Still haven't had a chance to start it with the seafoam in it.... Woodworking club tonight so probably won't happen till friday.
Benny
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(01-04-2017, 09:49 AM)bennybmn Wrote: I see what you're saying about the butterfly... I can see that happening on my lawnmower, but that's as easy as popping the filter off! It runs fine, and very smoothly with a little choke. So I get it that the choke is evening out the mixture, but it's still managing to pull enough total mixture in order to run. Seems fishy to me... see what I mean?
Edit: Still haven't had a chance to start it with the seafoam in it.... Woodworking club tonight so probably won't happen till friday. If it's running smoothly "with a little choke", it isn't running right. It's running lean. If it's running lean, you are risking blowing a hole in your piston.
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Oh I know it's not running right, I just meant it's not coughing or sputtering or anything. I'm gonna fire it up again tonight now that we have actual snow
 Seafoam is in there now. If it still needs choke, I'm going to drop the bowl and see if I can blast out the main jet with cleaner.
Benny
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