Hard start: no start
11-02-20, 11:24 PM
#1
Junior Member
Thread Starter
Hard start: no start
Hi friends
been tackling my 85 GSL with this carb issue. It was gummed up and we cleaned and put a new kit in it. Found that while running it the fuel pump pressure was high at 20#. So I bought a lower pressure pump, 5 psi. Adjusted the floats and it was running well. Let it sit overnight. Tried to start the next day. Would only crank. While choking it would want to try and start but did not start. Do I need to get a different pump? It seems like a carb engine doesn’t need a high psi pump. The first pump seemed to flood out the floats.
thank you!
been tackling my 85 GSL with this carb issue. It was gummed up and we cleaned and put a new kit in it. Found that while running it the fuel pump pressure was high at 20#. So I bought a lower pressure pump, 5 psi. Adjusted the floats and it was running well. Let it sit overnight. Tried to start the next day. Would only crank. While choking it would want to try and start but did not start. Do I need to get a different pump? It seems like a carb engine doesn’t need a high psi pump. The first pump seemed to flood out the floats.
thank you!
11-03-20, 04:26 AM
#2
What type of fuel pumps are you installing?
It is best to try to stick to the OEM Mazda pump with these cars. The 83-85 pump (N249-13-400B) is no longer available but perhaps you can find one, or see if the 79-82 pump (8871-13-400B) will swap in.
The stock carb wants a low fuel pressure, and it is a return system with no regulator, so it is very easy to end up with high fuel pressure, especially with a lot of the generic fuel pumps. It is not uncommon to require an aftermarket fuel pressure regulator (return style) when trying to run an aftermarket pump. 5PSI sounds quite high for the stock Nikki carb.
Also if the carb was gummed up and the original pump stopped working, I would be suspicious of the rest of the fuel system.
For the no start, if you had 20PSI fuel pressure you probably flooded the engine quite badly, you can investigate and try de flooding it, if you search the forums there is a procedure. Maybe check the plugs after cranking to see what they look like first.
It is best to try to stick to the OEM Mazda pump with these cars. The 83-85 pump (N249-13-400B) is no longer available but perhaps you can find one, or see if the 79-82 pump (8871-13-400B) will swap in.
The stock carb wants a low fuel pressure, and it is a return system with no regulator, so it is very easy to end up with high fuel pressure, especially with a lot of the generic fuel pumps. It is not uncommon to require an aftermarket fuel pressure regulator (return style) when trying to run an aftermarket pump. 5PSI sounds quite high for the stock Nikki carb.
Also if the carb was gummed up and the original pump stopped working, I would be suspicious of the rest of the fuel system.
For the no start, if you had 20PSI fuel pressure you probably flooded the engine quite badly, you can investigate and try de flooding it, if you search the forums there is a procedure. Maybe check the plugs after cranking to see what they look like first.
11-03-20, 07:12 PM
#4
Junior Member
Thread Starter
What type of fuel pumps are you installing?
It is best to try to stick to the OEM Mazda pump with these cars. The 83-85 pump (N249-13-400B) is no longer available but perhaps you can find one, or see if the 79-82 pump (8871-13-400B) will swap in.
The stock carb wants a low fuel pressure, and it is a return system with no regulator, so it is very easy to end up with high fuel pressure, especially with a lot of the generic fuel pumps. It is not uncommon to require an aftermarket fuel pressure regulator (return style) when trying to run an aftermarket pump. 5PSI sounds quite high for the stock Nikki carb.
Also if the carb was gummed up and the original pump stopped working, I would be suspicious of the rest of the fuel system.
For the no start, if you had 20PSI fuel pressure you probably flooded the engine quite badly, you can investigate and try de flooding it, if you search the forums there is a procedure. Maybe check the plugs after cranking to see what they look like first.
It is best to try to stick to the OEM Mazda pump with these cars. The 83-85 pump (N249-13-400B) is no longer available but perhaps you can find one, or see if the 79-82 pump (8871-13-400B) will swap in.
The stock carb wants a low fuel pressure, and it is a return system with no regulator, so it is very easy to end up with high fuel pressure, especially with a lot of the generic fuel pumps. It is not uncommon to require an aftermarket fuel pressure regulator (return style) when trying to run an aftermarket pump. 5PSI sounds quite high for the stock Nikki carb.
Also if the carb was gummed up and the original pump stopped working, I would be suspicious of the rest of the fuel system.
For the no start, if you had 20PSI fuel pressure you probably flooded the engine quite badly, you can investigate and try de flooding it, if you search the forums there is a procedure. Maybe check the plugs after cranking to see what they look like first.
Yes, the original fuel pump is hard to find, and I found this inline pump from Summit Racing which is an AC Delco 12v, barrel type pump with 4-6 psi. When it was running great, I pulled the return line and it was barely returning much fuel, and the float windows looked great. At cold start, the float windows still look good, but it wont start. I"m beginning to think I should change plugs?
11-03-20, 07:13 PM
#5
Junior Member
Thread Starter
11-05-20, 10:56 PM
#6
Thank you!
Yes, the original fuel pump is hard to find, and I found this inline pump from Summit Racing which is an AC Delco 12v, barrel type pump with 4-6 psi. When it was running great, I pulled the return line and it was barely returning much fuel, and the float windows looked great. At cold start, the float windows still look good, but it wont start. I"m beginning to think I should change plugs?
Yes, the original fuel pump is hard to find, and I found this inline pump from Summit Racing which is an AC Delco 12v, barrel type pump with 4-6 psi. When it was running great, I pulled the return line and it was barely returning much fuel, and the float windows looked great. At cold start, the float windows still look good, but it wont start. I"m beginning to think I should change plugs?
I had a no-start ordeal with my 80 SA. I swapped, dizzy cap, rotor, fuel filter, tried a 2nd set of ignition wires, even a pair of new igniters. It would NOT catch fire.
New plugs (old ones locked fine) - BOOM! off to the races. Felt like an idiot...
Stu A
80GS
AZ
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11-06-20, 01:15 PM
#9
Waffles - hmmm good
iTrader: (1)
Your plugs sound like they are fouled. Pull em, clean em up with a solvent and a wire brush, make sure to clear out the engine because it was probably flooded (make sure no sparks around) and reinstall.
Nikki will not work right with more than 3 psi and prefers 2.5 psi on the gas pressure. The pumps you have will flood it every time.
Nikki will not work right with more than 3 psi and prefers 2.5 psi on the gas pressure. The pumps you have will flood it every time.
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Cary Yamamoto (11-07-20)
11-07-20, 12:07 AM
#10
Junior Member
Thread Starter
Thank you for the information regarding the fuel pressure. Since the Oem pump is discontinued, it’s been difficult to source a substitute. Do you have a source for parts?
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