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DT6 Gummed carb

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rattlebolt

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"So the guy shows me a beautif

"So the guy shows me a beautiful little sail drive with a battery charger installed and I give him a bunch of money and take it to my boat. I fill it with fuel and start pulling the rope. And pull. And pull. I pull the plug and it's too bright to see the spark, but holding the wire with my hand against the block gives me a clear certainty that the cdi is giving the juice. I shoot some starting fluid and get some little revs at last. But no fuel is getting through the carb. So I pull the carb and find ugly gum at the lowest parts. A sailer has got to fix it on the spot with what he's got at hand right? And so I start cleaning the holes with my pattented piece of speaker wire in a cordless drill. I work over the jets. I look at the bottom of the float bowl and clean that out. And there's a needle valve down there of some sort, so I pull it out and clean it up. I didn't touch the needle in the upper section of the carb (if there is one). But I did run my improvised soft wire brush up the main jet tube. a little ways. My eyes just are not good enough to see what's supposed to be up there so I didn't strip more than an inch of insulation off. So the adjuster screw was moved and the main jet was cleaned out and the main ventury tube was cleaned partially. I put it back together to see if I had done any good thinking that the gum stayed low. And after a few pulls and a shot of ether followed quickly with the choke (pulling debris through) it started to suck gas and run. It idled like a dream. It reved up to the midrange perfectly. It went into gear and held power fine. But if I tried to open it up it bogged down completely. I tried opening up the main screw adjustment, but there's this annoying little hole at the bottom of the bowl that drips the gas out of the bowl if I turn this screw out. Is it supposed to be that way? If I open the throttle more than half way the motor starves. I've probably got enough push to run the motor for a kicker. But I want it all. Where do I set that lower adjustment screw? What do I do about the leaking fuel when I kill the engine? Obviously it doesn't leak when it's running because it's sucking air through there. I'm thinking the venturi is still plugged. Or the mix is way too rich? Help me Mr. Wizzard!!"
 
"Now we can cut to the chase!!

"Now we can cut to the chase!! (BTW 1988) No top end? Something really gummed up in there! But what? FOUND IT! when I did my first clean out of the motor, I missed one of the jets. Stupid mistake, but I wasn't working on my bench at the time. The jet I found and cleaned on the dock was down inside the bowl. The jet I missed was up on the top of the carb. So the top end is back! We did a quick little ten minute run and it pushed my little boat up to about six knots by the meter. And after about an 8 hour run at 3.5 knots, that's just heaven! It may not seem like that much, but it's a lot to me. I throttled down and got a big clowd of blue smoke. So I'm still feeling like there's something left to do. Maybe I've got too much oil in the gas and maybe I've got the idle jet set too rich. Give me a shout. Once you've got it back together and running, how do you set up the carb by ear?"
 
no tuning the carb is simple

no tuning the carb is simple
turn it in very slowly until rpm starts to die
then stop there
turn it out until it starts to die
then between the 2 dies is where u want to be
 
"I went down to the dock today

"I went down to the dock today and pulled on the motor. Three pulls and it kicked right over from cold. I like that. There's a bit of a gasoline smell in the exaust, so I believe that I'm running rich. Rich is good on a sail drive. Rich is cooler. Rich is better lubrication. It's a little dirtier with unburnt fuel. And I'm not maxing the horse power. But a sail boat hull will give you maybe one more knot if you double the horse power output. Rich will smoke a lot more, but be more reliable for a long pull.

BTW What throttle setting for that "in till it kills, out till it kills, set it in the middle" thing?

I also need to know What is good compression for this engine. Give me numbers for good, acceptable and poor if you can.

And tell me about the hot shut down-check the plug thing. What does a good plug look like and what does a bad plug look like?

I'm only out about 3/4 of a turn on the air mix screw. That's rich right? Factory manual says start at 2 1/2 I'm told at the local shop.

thanks in advance"
 
"I wish that I had the time fo

"I wish that I had the time for that! Unfortunately they don't have a manual at my local giant new and used book store or it would be bought already. And by the time they could ship me a manual, this motor will be dead. Or it may live. I really need this info and I'm looking for you or someone else to help me out here on the net. This motor is in use by necessity. It's the only motor I have, and it's the only motor on the boat. Please help me out?"
 
The motor was started about a

The motor was started about a week ago and run for about six hours straight at full throttle. There was no sign of anything amiss. It ran beautifully. It started and shut down and re-started without a single hitch on the day it last ran. At just less than full throttle it seemed to run a little bit rough. But open it up and it seemed smoothe. I had it at about a quarter throttle for a half hour when I was circling waiting for a bridge to open and there was no excessive smoke. Frankly I just don't know. I decided to leave the one carb adjustment right about where I found it. I've got instant on and instant off and smooth operation over most of the range. So I'm feeling pretty good about it right now. I'll compression test the motor when I get around to it.
 
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