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Peewee V4

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Davewild

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View attachment ImageUploadedByModel Engines1461031134.113721.jpg hi all
Please help, i have nearly finished the carburettor. Hope fully you can read the drawing I have posted, i am confused about the air bleed hole. Firstly there is only one dimension .033 above the center line of the carburettor but no other dimension, I'm guessing its position is central? What exactly does the air bleed do? The note explain that if the engine leans out at full throttle increase the size of the hole by one drill size, surely if you increase the size the mix will get leaner? Can some one please explain its purpose and where it should be ? Thanks in advance.

Dave
 

Cogsy

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I don't know about how the thing actually works, but Steve Huck followed the procedure and it worked so you shouldn't have any issues. A tip he gave me was to drill and tap the position for the air bleed hole larger (I used 4-40) then make up a threaded bolt/plug that you can then drill the air bleed hole in. If you mess up and make the bleed hole too big you can easily make another bolt/plug rather than dealing with too large a hole in the body of the carb. Should take most of the stress out of fine tuning the air bleed hole for best running.
 

michael-au

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That small hole actually lets the fuel through into the carby

I think it's labeled wrong and is a bit confusing, the more you screw the needle out the more fuel can pass through the hole into the carby
Screw the needle in and it cuts down the fuel flow, the hole in the barrel is what controls the airflow
 
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stevehuckss396

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The air bleed is supposed to allow air into the carb at idle and be blocked by the drum when the throttle is moved off idle. The theory is that when the carb is adjusted to run well and rev up well it will be to rich a mixture at idle so a little air is mixed to lean it out in the idle position. instead of a hole I drilled and tapped mine. Now I can drill holes through 4-40 screws and use them like a jet. If I go too big I can just change to a smaller jet/screw. On my v8 the screw is tapered and used like a needle.
 

michael-au

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Sorry I missundersood what part you meant
 

Davewild

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Thank you all for your answers and time, I understand now how it works i think. It is drilled in the centre of the carb and once the throttle drum is in the idle position air passes through the bleed hole and is then admitted to the top of thr hole through the drum and then down into the carb/ manifold, as soo. As the throttle is opened the hole is covered.
Again thank you all for your time, i am progressing slowly, still got the carb to finish then the fuel tank, dip stick, I got two badly leaking exhaust valves, that bad that I can suck my finger onto the exhaust when turning the engine. Still a few more weeks yet, final strip down clean etc etc.
Again please, what oil do I use?

Dave
 

Davewild

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Thanks Steve, I took your advice and used a 2mm set screw for the bleed hole. As for the oil I dont think we got anything that thin on-board but I will find something, might have to use compressor oil until I get home.
Im thinking your V8 will be next Steve, is it much bigger?

Dave
 

Cogsy

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Still a few more weeks yet, final strip down clean etc etc.
How is the Peewee going Dave, did you ever get it finished off or is it still in progress? I'll be back on mine soon and I'm hunting up all the old threads in preparation...
 

stevehuckss396

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Thanks Steve, I took your advice and used a 2mm set screw for the bleed hole. As for the oil I dont think we got anything that thin on-board but I will find something, might have to use compressor oil until I get home.
Im thinking your V8 will be next Steve, is it much bigger?

Dave


I'm sorry Dave I missed the question at the end. The V8 is a little bigger having valve covers and much longer. It is still a 5/8 bore and stroke so if you did Peewee you should have no trouble.
 

Davewild

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How is the Peewee going Dave, did you ever get it finished off or is it still in progress? I'll be back on mine soon and I'm hunting up all the old threads in preparation...
Hi Cogsy
Yes the engine itself is finished, a few finishising touches to do on the radiator.
I have been trying to start it a few weeks ago, lots of noise but it wouldnt run properly, i stripped it down to bring home from work and have been so busy since I havent even unpacked it!!!

IMG_3448.jpg
 

Cogsy

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Looks fantastic! If it's making noise it can't be far off running... I'll hold my breath while I wait.
 

michael-au

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Nice engine David, great job, hope to see it running
 

bluejets

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Hi Dave,
Nice work.
Another Aussie engine builder here.
Several including 4 cylinder 25cc four stroke boat engine, runs on methanol, grinding machines for cams and also another for crankshafts.
Presently doing castings for a v8 among other things. Mate of mine keeps me busy with electronic requests for his engines.
Wondered about your valve seats? Usually we cut our inserts at the same time as the valves.
Eliminates any difference in fit which can be a big problem, including hard to start.

What part of Thailand? We get back to see the family in Khon Kaen province every now and then.
 

michael-au

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Hi Dave,
Nice work.
Another Aussie engine builder here.
Several including 4 cylinder 25cc four stroke boat engine, runs on methanol, grinding machines for cams and also another for crankshafts.
Presently doing castings for a v8 among other things. Mate of mine keeps me busy with electronic requests for his engines.
Wondered about your valve seats? Usually we cut our inserts at the same time as the valves.
Eliminates any difference in fit which can be a big problem, including hard to start.

What part of Thailand? We get back to see the family in Khon Kaen province every now and then.

Hi
I was wonering if you have any pics of you cam and crank grinder, would like to see them

Michael
 

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