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Mini bike engine


michael van's Avatar
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07-04-04, 07:55 AM   #1  
Mini bike engine

I bought a vintage mini bike I would say from the 60s it has a Tecumseh engine from what I can figure out it is a 4 horse.
Model #HS40-55290c ser# 1076D or O.Please can you tell me if it is 61 vintage or 71 vintage?
It has been sitting a very long time and the carb needs clean because I can smell that old fuel smell.Is this very hard to do on this engine?It has very good compression so I think once I get it started she will be fun thing to take out in the field (just like when I was a kid) but only 40 years later.The brand name of the bike is a Hornet.
Thanks guys for all the help

 
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cheese's Avatar
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07-05-04, 12:12 AM   #2  
Hello michael van!

Unfortunately, the tecumseh code does not denote the decade of mfgr. Just the years 0-9. If I had to guess, I would put my money on '71. Just because that was when the minibike had large popularity.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

God bless!

 
michael van's Avatar
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07-05-04, 11:52 AM   #3  
new question

Ok I took the carb off and took it apart (took the float bowl off) it was full of sludge and green gas.I bought a large can of Berryman chem-dip carb cleaner with the basket.
My question is the needle has a spring on it how is is hooked up?
Is the neddle hooked up to the float or is it made to keep the needle open?
do you have any pictures or links?also do you think I can leave it soak over night without harm.

 
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07-05-04, 05:53 PM   #4  
Did the needle come out when you pulled the bowl & float out? If so, the needle & float work together to keep the fuel level in the bowl constant. The needle should be pointing up. The spring/clip should connect the bottom end of the needle to the float so when the float goes down it pulls the needle out and lets in more fuel.

Did the needle & spring come out when you unscrewed something from the carb.? If so, it should be a jet needle (high speed or idle) and the spring helps keep it from vibrating loose.

Carb. cleaner, lacquer thinner or MEK are also good for removing varnish.

 
michael van's Avatar
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07-05-04, 06:20 PM   #5  
Yes it came loose

Yes when I removed the bowl with has a nut with another needle in the middle of the nut(I did not mess with that one) it also has a drain on the bowl.
Anyway the float was stuck from the gunk I pulled it down and the needle stayed in but the float came down.But now I know that the spring attaches to the tang on the float. .
I have it sitting in the cleaner now it has been several hours and is cleaning up nice.However the passage for were the fuel comes into the bowl is still blocked I managed to clear it with some weedeater string.I also think it might be good to fill the tank with the berryman after I get the carb parts out It might have a screen and if so I can only imagine how it looks after pulling the carb apart.I will keep you guys up to date.(the berryman ate the paint right off the carb) good stuff

 
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07-06-04, 07:10 PM   #6  
Problem

I tried to put the needle back in the seat but it will not go down enough,The float will not lift up with it in place.
Is the seat rubber maybe the Berryman wiped it out if so what can I do?

 
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07-07-04, 01:30 AM   #7  
Yes, the seat is rubber. It is a part that any small engine shop should have, and it comes with a new needle and spring clip. Make sure you don't have the float installed upside down...that's more what it sounds like.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-07-04, 03:15 AM   #8  
Ok

Ok thank you I was afraid of that it looks all swollen up.I guess I will have to take it in to the shop after all to have them replace the seat.
It is not upside down I tried it both ways.The only way the float has full travel is with no neddle.

 
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07-08-04, 01:00 AM   #9  
You can replace it yourself, it's easy! Go pick one up (around $3.00). Use a small wire or thin wood screw to pick out the old seat, check to be sure the seat area is completely clean, and use the blunt end of an appropriate sized drill bit to push the new seat back into place. Make sure the side of the seat with the ridge is toward the carb body.


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-09-04, 05:55 PM   #10  
I will get one

Ok I will take the carb in to a local small engine repir shop here in Grapvine Texas and see if they can help me out.I hope they still have parts for this old engine.

 
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07-10-04, 12:33 AM   #11  
They should, it takes the same seat that the modern carbs use.


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07-18-04, 08:35 PM   #12  
Update

Thanks guys I took carb to the small engine repair shop and as soon as I walked in the old guy says Hey thats a real old Tecumseh carb,I knew I was in the right place .Hey went to a I told him I need the kit he went right to a drawer and pulled out the kit.
He took it back and insalled the kit for free (I bought the kit)Came with new low and high speed needle screws new O rings and the much needed float seat.
9 bucks
Got the mini bike running today and I tell you it hauls butt my wife clocked me at 30 mph.
Paint job is next Thanks for the help

 
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07-19-04, 08:54 AM   #13  
Need a little more help

Well the same engine that ran so good yesterday now wants to shoot fuel out of what I think is the vent for the bowl.It is a little hole on the side of the carb.I put gas in tank and it shoots out of the hole.Do you think the float is stuck open.Why would in run good one day and mess up the next day?

 
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07-19-04, 02:54 PM   #14  
Most likely you have a float that isn't floating, if he in fact installed a new needle & seat...correctly! I will say that if you brought a carburetor to my shop, I would insist you leave it with me so I could soak and recon it. But that's just how I would do the job. Free labor is good, so long as it works out well.

 
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07-19-04, 03:28 PM   #15  
Brass

The float is a brass circle I did not feel any fluid in it when I shook it.I am going to take it apart tomorrow to see whats going on.maybe the hinge might need polished.
If the float is bad can I solder it if it has a small hole since I do not know if you can get one anymore?

 
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07-19-04, 10:26 PM   #16  
It's a common float too...you should be able to get one at any small engine shop. I wouldn't try to solder it...most times you can't even see the hole, if it has one.


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07-24-04, 09:03 AM   #17  
van

Any luck yet in figuring out your leakage problem with your carburetor?

 
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07-24-04, 09:30 AM   #18  
not yet

We have a house full of people here and they brought there dog so I am kinda on hold till they leave .I hope it is soon my nerves are frazzeld.
I will let you know.I hope soon.

 
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