Ok, I've searched and found a lot on FC hot start problems but not much on FB. 1st: 81 GSL 12A. 125kmiles. complete RB header exhaust system. rats nest removed and air pump except for a/c solenoid. Car starts right up when cold in summer with no choke. After driving for any length of time if the car sits for more than like 15-20 min. it just does not want to start. Have to pump the pedal like 20+ times and then hold down the pedal when it tries to start to get it to fire. If after warmed up and shut car off for 1-5 min of duration,car will start back up. Its just after the " heat soak" that it has problems. I read somewhere about low compression? I also know that hard starting is kinda normal for the rotary but this is nuts.

 

Try putting the pedal to the floor and holding it there, then cranking. I have found it greatly increased the chance of a hot start in mine. Typically hot start problems are due to flooding, and pumping the pedal a ton will only make it worse (assuming your carb is in good working condition).


Isaac

 

Do you still have the "hot start assist" assembly in place, or did it go with the rat's nest?

Without it, you have to hold the throttle open manually to help a hot rotary start. Pumping actually makes it worse, since you're juicing more gas in with the accel pump. More air is what you want.

Right before you try your next hot start, check the fuel levels in the carb bowls, see if they are excessively high or low. heat soak on the carb can cause bowl levels to drop.

Try this:

1) key on
2) wait 10 secs or so for fuel pump to fill line and bowls
3) gas pedal to floor and hold it
4) key to start

See if that works better.

 

When I first got my car I had this problem, though it was bone stock then. A new battery fixed the issue, so check yours if you haven't already.

 

Divindriver, yes it is still there. Is/was there a solenoid for that? I just hooked the vacuum line back under the carb. Thanks for the info.Rob

 

Nope, HSA is fully electrical. It's switched by the ECU depending on the temperature sensed by the #2 temp sensor on the rear of the water pump housing.

 

I think if you just let the pump run for a few seconds it might fix your problem.
Your float bowls probably siphon gas back out when the pump stops and the
fuel in the line settles back to the pump. Thats why it starts if you leave it for
only a few minutes but after 20 or more the bowl is empty, no gas.

Check you bowl levels before you try a start after sitting and see if this jives
with what I've said.

 

After driving the car until warm, shut it down and remove the air filter housing from the carb. Watch the carb over the next few minutes to see if you have fuel flowing into the barrels of the carb. This is a fairly common issue, which leads to flooding and hard hot starts.

Another thing to check would be your timing, which can also lead to hard hot starts.

Good luck.






.

 

Have you checked the condition on your igniters?
If none of the above solves your problem it might be a bad igniter that causes it!? Atleast, that´s my experience when it comes to hot-start related problems.

 

Sorry to thread necro. What are the common causes of this? My carb does this, primaires and secondaries completely full of gas and car floods. It makes it a real PITA to get started again, and once it finally does fire over it runs like a turd for a while.

 

What I can think of off the top of my head:

1. Float bowl vent solenoid disconnected or inoperative.
2. Restricter in fuel return line missing or installed backward (not sure if direction matters).
3. Charcoal cannister system. There is a small orifice that can clog and cause this.

Hope this helps.