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78 620, L20B foreign matter in combustion chamber.


Atikin9000

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Steamy exhaust on cold start up in the cold is normal. The choke adjustment is only for setting when cold. All electric chokes should warm and turn off in 5-8 minutes. Take the top of the air filter off and look when it's warmed up and see if open.

 

 

The temp sender is on the front of the thermostat housing and has a Yellow/White wire... that may have fallen off. 

 

If the wire is on, take it off and on a couple of times to clean and make better contact.

If still no good, ground the wire does the gauge read FULL HOT.

 

YES.... the sender is bad

No......  If still not working, does the gas gauge work?

 

NO..... Both gauges do not work... the volt regulator for gas and temp is not working

YES...  Gas gauge works... there is a break in the wire between the gauge and the sender.

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So I was wondering about re torqueing, I have maybe 5 or 6 miles on it and a total of an hour of running time between idling and me taking a couple of short drives. I was thinking of checking it tomorrow but I’m just wondering if it’s better to wait or just check multiple times.

 

I know a guy that blew up his 521 cause he didn’t retorque.

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So I was wondering about re torqueing, I have maybe 5 or 6 miles on it and a total of an hour of running time between idling and me taking a couple of short drives. I was thinking of checking it tomorrow but I’m just wondering if it’s better to wait or just check multiple times.

 

I know a guy that blew up his 521 cause he didn’t retorque.

That is a Z24 thing as far as I know, maybe Z blocks in general, I never heard about this re-torque thing involving L blocks. 

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Well it ran fine yesterday with a high idle around 1200-1300 and it occasionally would stall out, went to start it today and it sounds like this, choke is off and it continued sounding this way and stalling past 1000rpm even after it warmed up pretty good, any thoughts?

 

 

I took a short sound clip in the dark if you’re curious to hear how it sounds.

 

 

And here’s a clip from yesterday.

 

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After stewing on it for an hour, it sounds like a slight miss, might have fouled plugs, I’ve also been messing with this carb for the last 3 days with no luck.

 

I did re use the old carb gasket along with a new thinner one stacked, and now I can see some gas around the sandwich plate between the carb and intake, maybe nice vac leak. I’ll do some checks tomorrow.

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That's exactly what a rich mixture will do. You'll start dropping cylinders.

Had a slight vac leak on the fuel rail, also the spark plugs were absolutely fouled.

 

I’m gonna have some one look over the carb that’s a professional lol and I’ll check the plugs again see how she’s running.

 

 

Runs smooth but stalls out as the rpms drop with the choke wide open, with the choke closed runs like garbage.

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