Solex 40 PII-4 Problem..Help!

ron69912t · 05-14-2002, 08:42 AM

My 1969 912 Targa has split-shaft Solex's that were impossible to syncronize with a UniSyn. Only the front air-mix screws worked the other two rear ones were dead.

So I rebuilt both carbs and set float height and accellerator jet volume to the shop manual specs. The plastic floats were OK too no leaks and moved freely. Did not find any plugged jets either.

Installed the carbs and was amazed how smooth the engine idled at 900 rpm and all 4 air-mix screws worked. I also easily Syncronized both carbs to the same levels, never ideled so nice.. I was about to put the air cleaners on when the right carb started to overflow gas out the center brass overflow tube. Looked like a small mini fountain.

I shut off the engine and removed the carb cover while it was on the car so as not to disturb anything. I then replaced the float needle valve with the old one thinking the new one was defective. I noticed the gas level in the bowl was NOT overflowing and was at the proper fill level at the level plug hole. I blew through the float needle valve I had removed and it seemed to work OK. What happened to all that gas coming up out of the float chamber, you would think it would have filled up the float bowl then run down to the floor.

Started her up again and tried to adjust the air-mix screws again, she started to pop from both carbs and the gas overflowed again from the same right carb. I shut it dow ASAP for fear of a fire.

Could there be some back pressure coming up from the right cylinder bank from an unseated intake valve? I plan to check the valve clearances tonight. Maybe as the engine warmed up something changed.

The manual warns of "combustion blowback" up through the carbs as a potential fire hazard.

Has anyone had a similiar problem and fixed it???

Also checked the timing with my Sears dial timing light at 5 degrees advanced for my 050 mechanical Bosh distributor before I removed the carbs for rebuilding just to be sure it was OK beforehand.

Thank for all your help.

Ron D

ron69912t · 05-16-2002, 05:17 AM

I reajusted the intake valves, they were a little too tight.

Then I made up a hose connection to the gas inlet port to the problem carb to blow through as I experimented with gas float bowl levels, needle valve changes and needle valve gasket changes. I discovered the kit gasket for the carb cover was thicker, the kit needle valve pin was a different length and the gashet I used was too thin. All combined the differences stacked up to about 0.060". This was enough to prevent the needle valve from shutting off when the float was topmost. I used my old needle valve and tried different gaskets for it until it opened and closed with float bowl gas level changes. Ran the engine for 1/2 hour with good results. Plan to drive it tonight.

Hope the problem is solved, funny I put all new gaskets and a new needle valve & gasket from another kit on the other carb and it worked fine! Go figure.

FYI

RonD

craign · craign's Garage

Take a fire extinguisher with you on that test drive though........just in case!

Craig

ron69912t · 05-16-2002, 10:51 AM

Craign:
Thanks for the warning. I always carry one inside the car.

Never can tell, ugly thought.

I plan to idle it for a long time before the drive to be sure.

Thanks
Ron D

timmy · 05-24-2002, 07:44 PM

hey Ron 912 this is Timmy from Las Vegas [sunny warm Las Vegas] ok, now take the carburator off that is flooding out. take off the top and set it aside, then the gasket taking care not to rip,tear it, take out the float, set it aside now this is where I think your problem is, there is a small brass piece above the float with a notch out off it then comes the shaft piece with the straight pieces , they have to be in order to work right , place them back in in this order, thin straoght piece with flanges wrapped on it, this one goes in the farthest groove/notch away from the float with the flanges protuding into the next groove, place the float in the second groove over the flanges , the float is in one groove all by it self, then the brass piece wqith the notch over the pin/flange , pin flange piece ,and brass with notch out off it in the same hole [out side hole/notch] float in the center inside notch all by it self, hope this helps you if not call me and I will talk you through it on the telle-phonee- later dude air it out topless targa style bye. ymmit@lvcm.com
1-702-642-1151

timmy · 05-24-2002, 07:50 PM

hey ron I just made a bit off a mistake I gave you th einstructions for a solex, p eleven 40 s sorry so now the thing to do is take the other top off the good carb, making sure how it is put together, and do the other one the same using the good carb as a example, sorry , but it is in the float , the problem is , I had gas running out the tops of mine before , this was the cure I am sure check the one with out the problem and the rest is history sorry about the solex mishap later timmy

Kneshoba · 07-02-2002, 01:49 PM

Try backing out your float adjustment screw.

I had the same problem last weekend, and a friend of mine came by and fixed the problem.

adot · 07-02-2002, 03:27 PM

Hummmm

I think its :

out = higher the gas in the bowl
in = lower the gas in the bowl.

Again not 100%

Brett

dimps8 · dimps8's Garage

Ron, I also had the same problem last weekend. right hand carb would flood. I problem was the hex on the new needle valve was pushing the float down and not shutting off the fuel. I had to use a thinner brass washer and align the hex flat parallel with the edge of the carb top lid.

adot · 07:27 PM

Hey Ron

Where did you get the rebuild kit from? Seems others are having trouble with rebuild kits also.

Damon, how about you

Maybe bad rebuild kits from somewhere

Thanx
Brett

912UK · 912UK's Garage

Hi I have been having the same trouble with my carbs. The kit I had for the car came forma supplier in the UK but he gets all his stuff from stodards. To honest the kit I had from him looked abit naff. I even told him to. alot of the gaskets needed finishing and the brass floats where not finished very well (swalf) on them I will now go and have a look at mine as this thread has been very use full also a friend has had the same problem his right hand carb kept flooding again all using this kit. these kits could be the problem and poss dangerous.

mark

ron69912t · 08-15-2002, 04:43 AM

Sorry for the late reply, was on vacation.

I bought two Solex rebuild kits from PP. The gaskets looked ok but the replacement shut-off brass valves looked like less quality than the old ones. One new valve worked fine the other was not used, I reused the old one.

My guess is that they all get the kits from the same manufacturer located in China or the like. I doubt that they inspect them for quality either when they arrive.

I have solved all my Solex problems now and in the future...I switched to Weber 40IDF's. Man what a difference, runs like it was new. Idles like a purring kitten and no more spitting or popping. No stalls at the stop light with cars going around me honking.

Thanks,
Ron