Engine bods need some tec help.

912UK · 912UK's Garage

Hi I have just had a go at my other halfs 912 unit in her speedster. I have replaced the 009 for a 050 disy and checked the valve adjustment ( a job I have been wanting to do since buying it ) Clocked it all in did the valve adjustment the one side 1 & 2 were well out too tight. 3&4 were near correct but still too tight really.

Any way I fired it up and it ran but missed and was a pain to get off the mark. So back in the garage and I wipped out the plugs and found them sooted up on all 4 but 3&4 were wet with fuel.

Cleaned them up ( this has worked in the past when the 009 was in and it ran great but then in time same problem ) Any way I wipped off the air cleaners and looked in the carbs all looked ok and the flaps open togeather (twin shaft) fuel came out all the right bits.

Fired up again it did not want to know, then it went and it backfired though no 2 carb ?? with a small flame ( cool well not so cool) .

So what's the prob and do I have too much fuel going though the carb to No 3&4. How do I reduce the amount ? ( Float adjustment ?)

Also when it did run I did the Maestro trick ,dropped the link to the left carbs and reved the engine it ran fine on 1&2 carbs but 3&4 it coffed and died. I also wipped out the plug to no 3 and left it out it still ran the same no different. so at this stage the car was only running on no 4.

It has always run real rich.

Any idea's

M

tronman · 03-24-2003, 08:06 AM

Sounds like either the float is sticking and causing the carb to flood badly or possible there is something keeping the needle valve from fully seating on that side(a bit of trash that found its way past the filter...). I'd pull the carb and tear it down and clean everything well...paying close attention to the float making sure it moves freely and the needle check valvle to make sure it seats and seals properly. If all looks well adjust the float level to keep it from flooding...starting point anyway...

912UK · 912UK's Garage

Cheers Kev I will have a look at it. my 912 I had the carbs rebuilt by a guy Andy Prill uses here in the uK. Very cheap for what he did £360 for the pair all in inc vat and shipping. But if it looks like a bit of crud I will give it a go and have alook. It does look to be a carb problem. I will have a look at the needle float as I have had this before and was kind of looking at it but it was late and I thought I would need to get a new gasket after I took the old one off and it all got too much and a glass of wine was calling me.

but a night sleep and a new look I think I will have the carb off and look.

I am sure it is in a book some where but how do you go about adjusting the float level?

I also adjusted the valves as Duane Spencers book said and did an extra 1/1000th on each valve so 7 insead if 6 ,5 ---4 etc too much ?? I have heard from Rodger Bray here in the UK to have the cars sounding like a sewing machine to be on the safe side??? Not too sure about that bit.

let me know cheers for taking time out to help

Mark

tronman · 03-24-2003, 11:43 AM

Are you running Solex or Webers? If you just had them done I'd lean towards the float level being too high...if they are Solex you can adjust it with the set screw on the side of the bowl...Webers you have to get inside and "lightly" bend the tang that the needle valve attaches to the float on...either way its not hard. Also if you are careful and since they are freshly rebuilt you should be able to to reuse the gaskets...

tronman · 03-24-2003, 02:15 PM

Hmmm...now that you mention it I think you can...I'm never going to hear the end of that am I? Heheheheh....

tronman · 03-25-2003, 06:59 AM

Heheheh...I make one little mistake(well its the only one I'm going to admit to)...its great to have friends with long memories.

Morrie · 03-25-2003, 09:04 AM

I post all my mistakes on my website so if you ever get to feeling bad....

http://morrie.larson.freeservers.com

look at the journal and you'll feel better.

Morrie

912UK · 912UK's Garage

Got the car running OK now with the 050 but still too rich on the left hand carbs so much so that the plugs are wet with fuel so this sounds like too much fuel how do you adjust the fuel rate to the one carb. Also I wounder if some one has messed with the jets ??

M

Green 912 · 04-05-2003, 02:20 PM

Need the answer to Webber or Solex queston.

912UK · 912UK's Garage

SOLEX

The plugs on that side soot up alot and are soaked in fuel once they come out. I clean them and run the car fine and then it does it again leading to a miss fire and loss of power it is that side as I did the Harry Pellow trick and disconected the carbs the one side 1&2 ran fine 3&4 ran rough as hell

M

snowman · 04-07-2003, 10:28 AM

THe first trick is to adjust the float levels in the carbs. There are several books as well as the factory manuel that tell how to do this.

But wait, I jumped ahead to far. Do as Kevin suggested and tear it down first. Make sure there is no junk anywhere and that the needle valve isn't sticking. While it is apart you can check to see if all the right jets are in the right places.

Back to assuming (never a good idea) the thing is put togather right the float should be adjusted. Also check fuel pressure, if you have an electric pump it can be to high for the float to close, and yes one could work and another not work with slightly high pressure.

The only trick in adjusting valves is to make sure the engine is cold. Use the factory specs unless it was just revbuilt.