77 Bus - problem starting after engine warmed up

It may be a carb flooding issue. What engine do you have and what carb?

You might try turning the engine by hand both when cold and when hot to see if there is any difference in effort required.

Speedy Jim

Jim, I have a 1600CC single carburator engine.

Identification of the carb:

This is the information found on the side of the carb. Solex H30/31PICT Ind. Bars

So from that I looked on line and found Solex 31-PICT and Solex 30-PICT but I am not sure which one of the two it would be since the nomanclature is different on the carb vs what I am finding on line. Chuck

Flooding *can* be a problem. Most common in summer temps. After the engine bay heats up, fuel may boil in the carb bowl and dribble down the manifold after the engine shuts off.

Also, a float needle valve which doesn't shut tightly can allow excess fuel to overfill the bowl. Some fuel pumps build up pressure in the outlet as the ambient temp goes up, with the engine not running. That can force open the float needle.

One thing you can do: Immediately after shutting down a hot engine, remove the engine hatch lid and take the air cleaner off so you can look down the carb throat. Use a flashlight (torch). If you see clouds of white smoke (vapors) or even dribbling fuel, flooding is the likely result.

I don't want to lead you astray with a red herring, but the above is common and should at least be considered as a possibility.

Speedy Jim

I live in a warm weather climate, 78 degrees fh today. So it is a direct possiblity. I will check as you suggested.

What can I do about it if it is the case, besides moving to Michigan :-) ?

Thanks Chuck

Hi,

I had a similar problem and it was my electric fuel pump pumping 6 psi, when 3 was fine. So I used a regulator and all is fine. But I hate to say it, once I had the same problem and it was my valves and heads. Once hot a valve or a head would warp or leak and I lost compression. IN a rush I would hose down the engine and it would start right up. I hate to say the words -- COMPRESSION TEST if it is not flooding. Joe

Before you get too deep into this and that, do a compression check. At the very least, pull the plugs out and see if one of them is significantly different in coloration from the others (#3) If they are all perfect looking, maybe skip the compression check, but if it was me, I would check that 1st if nothing else, to put my mind at ease. It is a typical symptom of a number of things, one very common one is cracked head or valve trouble. If it starts right up when you compression start it at a higher spinning speed than the starter, perhaps this is a factor. If so it should also have trouble idling smoothly when hot. Hope it's not your problem, but good chance it is. - Bah

easiest way to cope with it is crank with the gas pedal to the floor. it should start much easier if its flodding.

I have a similar problem with one of mine - If its hot but the choke has cooled (ie back ON ) then I find it helps if I have the ignition switch on for 30 secs to a min for the choke element to warm up before trying to start.

Rich

Eduardo K. wrote:

I checkedthe plugs and compression and other then number 3 being a little lower then the others everything looks fine.

I took an evening a rebuilt the carborator, and that seems to have done the trick. I suspect the needle valve was leaking slightly.

One other thing that I did that may have helped. I put a relay back on the fuel pump so that the pump will not run unless the engine is spinning. The pump used to run with the ingition key on even if the engine was not running. I don't think this was a major hit, for this issue, but it sure seems to be safer. Chuck

how do you turn the engine by hand?

Patriotism is supporting your country all the time and the government when it deserves it. -Mark Twain

If I recall, his was a 1600cc upright. Grab the GEN pulley and turn. If the belt slips, put a little hand pressure on it.

On a later Bus, put a wrench on the ALT pulley nut. This works best if the plugs are out, but you can do it with plugs in turning slowly. Or, take the mesh screen off and turn the crank/fan pulley.

Speedy Jim

Grab the belt & upper pulley. Or use a 21mm socket (Spark plug socket) on the upper pulley nut.

Jan