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VW hard starting after warmed up

JimVT

JimVT

Bronze Member
My snow trac doesn't fire up righ away after warmed up . If it sets long enough to cool or in the morning when colded it starts immediately. I have to crank it 30 seconds one or two trys and it starts when warm.
I have the 1200cc engine with a larger new automatic choke carb. It was all tuned and valves set at a shop.Tming could be still advanced slightly and carb set for 3000ft to make it run cooler. I still have points .
Lyndon and I thought it was a altitude air pressure problem because It did it only at 4000ft. ButI been having it do it at 700ft .
Could the auto choke be out of adjustment and it floods. It starts like it is flooded.
i been running it all last season this way and really need it fixed or I'll be losing the hand crank starting contest at our meet next month.
jim
 
Wonder if it is boiling the gas in the carb as it sits when warm. Check the temp of the carb and see if it gets warm to the touch when you park it. Try rubbing a hand full of snow on it to cool it down. If it gets warm it might be preventing the choke from closing to start it.
 
JimVT said:
My snow trac doesn't fire up righ away after warmed up . If it sets long enough to cool or in the morning when colded it starts immediately. I have to crank it 30 seconds one or two trys and it starts when warm.
I have the 1200cc engine with a larger new automatic choke carb. It was all tuned and valves set at a shop.Tming could be still advanced slightly and carb set for 3000ft to make it run cooler. I still have points .
Lyndon and I thought it was a altitude air pressure problem because It did it only at 4000ft. ButI been having it do it at 700ft .
Could the auto choke be out of adjustment and it floods. It starts like it is flooded.
i been running it all last season this way and really need it fixed or I'll be losing the hand crank starting contest at our meet next month.
jim
Click to expand...
I would suspect the carb is the trouble .Auto chokes can be a pain .
 
first off Allen is wrong the electric choke should work fine i have had no problems with mine .you have remote mounted gas cans put a ball valve in line and shut it off when parked, my guess is the float valve is leaking a little bit and flooding with that tank high the siphon efect can cause enough head pressure to over come the needle and seat. i have had this problem intermidently on mine now i just shut off the ball valve as that is for shure. also i have had enough leakage in the past that it has hydrolocked the motor and gottten past the rings into the oil. this is why i don't advicate a high mounted tank.
 
Hi Jim I am with Don, Are you holding the throttle open to allow extra air in while cranking it warm.?

Could the tank vents be shut plugged?

electric choke could be set a bit rich, note temps when it is giving you the business. Of course you could look at the idle cam on the outside of the carb to see if it is shut during this starting attempt.
 
I am in agreement with Don. Install a valve on your tank and shut it off every time you are done with a ride. I did this with my tanks. I too had a problem with it draining into the oil reservoir. Learned the hard way and had to replace brand new oil. :whistling:

Good luck and have fun out riding. It is still -42 F at my cabin. I am hoping that it warms up so I can get my Snow Trac out for a ride.:ermm:
 
I have the fuel connected for weeks and it fires right up but after warmed up and turned off even for 30 seconds it is hard to start. If it cools before starting again it fires right up. Do I really need to turn off the fuel for a climb out of the cab and back in situation. Can the carb be leaking that fast?
 
snowtrac jim said:
just a gess .over heated ignition coil week spark when hot. dirty rotor arm /dizzy cap.
Click to expand...

Worth checking out for sure....I am thinking it may be a spark issue not a fuel one. Fuel will not change when warm or cold, as long as there is not too much, and your needle and seat are OK. But your ignition system can change as the temps go up. I've seen this hot coil failure before, and it is a hard one to figure out.

I had a V6 GMC gasoline engine that was a bitch to start when hot. A new set of points fixed it every time....

Regards, Kirk
 
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JimVT,

I don't think it would be that quick. Usually I just let mine run if I am just getting out for a minute. Might have picked up some grit in the carb. Have you used some carb cleaner?

Hope that it is not too elusive. Hate having to work when you could be out playing.
 
on adjusting the auto choke is this the correct way? I set it so it just starts to close when warm. It has the wire to the choke part so it must be heated by electricty to open it.
My 64 bug in 1969 when i was 17 was much easier.
 
when adjusting auto chokes i set them up to close when cold must be below 0 and look for a firm closing also you can use a co2 fire extuinguisher to cool the choke stat
 
300 H and H said:
Worth checking out for sure....I am thinking it may be a spark issue not a fuel one. Fuel will not change when warm or cold, as long as there is not too much, and your needle and seat are OK. But your ignition system can change as the temps go up. I've seen this hot coil failure before, and it is a hard one to figure out.

I had a V6 GMC gasoline engine that was a bitch to start when hot. A new set of points fixed it every time....

Regards, Kirk
Click to expand...
i have to agree that a hot coil or improper coil saturation from a incorrect point gap or bad coil could also be the problem. if you could find some one with an old sun machine they could tell you if you have an ignition problem.
 
A common problem on VW's and air cooled Porsche's . Usually caused by fuel boiling over when the carb is hot or a worn throttle shaft. Easiest fix is to hold the petal to the floor and crank it till it starts being careful not to over rev the engine. The extra air thins out the raw fuel. A new carb would also fix the problem.
 
I would suspect heat related boiling of the fuel in the carb.
One thing that is also good for electric chokes is to have an oil pressure switch actuate a relay that applies the power to the the electric choke. this prevents the choke heater from warming up until you have actually strated the motor.
 
that is a good point i have 2 carbs with electric chokes, and i have had to adjust both as i found them too tight. i set them up when cold out side about 30 degrees ,so the choke butterfly closes lightly and it has always worked for me .and have had no need for the op switch
 
At the jamboree we looked down the carb and seen fuel comming in when stopped. after I let it set 3hrs and it fired right up. Could the valve be sticking in the carb? It runs good . The vw H30/31 PICT SOLEX carb is oversize and 1 year old.It was put on by a wv shop when a tune up was done. I plan on pulling the top off the carb and checking the float valve. I can start it right up if it doesn't set.
jim
 
Is it hot enough it could be boiling gas in the bowl? Gasoline's boiling point is well below waters I am thinking. Maybe in the 180-190 range?

Regards, Kirk
 
Try a new needle and seat. Most carb kits come with two thickness gaskets for for this valve. Use the thicker one. Make sure all your jets are secure. An insulator plate between the carb and manifold would help but I haven't seen any. If it doesn't fire within a few seconds put the petal down [don't pump it] and keep cranking. Also check your float for fuel saturation or leaks.
 
Hey Jim if I could put my 2 cents in my bet would be on the needle and seat(if your carb has one). I had a slead do the exact same thing although 2 stroke it would start like a dream when cold but if I let it run for 5 mins shut it off it would not restart BUGGER! Good luck hope you get er fixed
 
Got it fixed
It took a few hrs of troubleshooting . After trying a new float valve and still having the throttle plate covered in fuel after two minutes. We bent the float so it put more pressure on the valve. No leak! The float was good but just bent some how.it also needed a carb adjustment.
Thanks
jim
 
Glad to hear your problem was resolved. Your carb must have had the older round float that can be bent.One other approach that would work is is to put two gaskets under the float
 
Jim now you can see why i don't like a high mounted tank if you had the tank in the origional location this may never had showed up i have had leakage to the point that it hydro locks the engine when this happens you usualy gas down the oil to. i really want to get my tank back where it belongs.
 
i been unhooking the fuel line when I stop .I remember you talking about that in the past. We'll see if tweeking the float lowered my fuel level when i climb the next hill.
I have a 5000ft mountain to climb next weekend.
jim
 
As long as your needle and seat are good and your float is ok you should have no problems with gavity flow from your tank. Unless it's creating more than 5lbs press when it sets.
 
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