Need help diagnosing this problem...
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Mountain Pass
Joined: Nov 2019
Posts: 142
Likes: 0
Need help diagnosing this problem...
I have a 360 rebuilt Fe motor that whether its warming up or at operating temp the rpm will drop and cut out causing the motor to die. I know i have all the vacuum ports blocked and everything but i just cant figure it out thanks. If you want a video go to my you tube channel called BigBlockBumpside and i will be the latest video.
Cargo Master
Joined: Oct 2011
Posts: 2,251
Likes: 303
From: Kenner,La.
360
Have you tried closing the choke when the engine starts to die?
Also get a volt meter and connect it to the coil “BAT” terminal when you start the engine and watch to see if the voltage drops below 7-8 volts after the engine starts to slow down and stop.
Also get a volt meter and connect it to the coil “BAT” terminal when you start the engine and watch to see if the voltage drops below 7-8 volts after the engine starts to slow down and stop.
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
With the tach jumping and then just going to 0 and the motor shutting down like the key is off to me points to the IGN side of things.
What are you using on the IGN side to make spark?
I take it you are holding the RPM up at the 1500 mark and let it drop down to the 1000 then back up?
If so what carb you running? The fast idle needs adjusting and maybe the choke?
Dave ----
What are you using on the IGN side to make spark?
I take it you are holding the RPM up at the 1500 mark and let it drop down to the 1000 then back up?
If so what carb you running? The fast idle needs adjusting and maybe the choke?
Dave ----
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
Fuel issues does not cause that.
Dave ----
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
[QUOTE=FuzzFace2;19159175]Did you see the video and the tach jumping and then drop to 0 like the key was turned off.
Fuel issues does not cause that.
Dave ----[/QUOTE
That's exactly what fueling issues do as they starve. This is most probably a fueling issue and it takes but 2 mins to rule out improperly adjusted idle ait mix.
Fuel issues does not cause that.
Dave ----[/QUOTE
That's exactly what fueling issues do as they starve. This is most probably a fueling issue and it takes but 2 mins to rule out improperly adjusted idle ait mix.
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
To me it drops too fast to be a fuel issue. I also don't hear the motor trying to stay running like when it runs out of fuel, it just cuts off.
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
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Mountain Pass
Joined: Nov 2019
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To me it drops too fast to be a fuel issue. I also don't hear the motor trying to stay running like when it runs out of fuel, it just cuts off.
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
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Thread Starter
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Mountain Pass
Joined: Nov 2019
Posts: 142
Likes: 0
To me it drops too fast to be a fuel issue. I also don't hear the motor trying to stay running like when it runs out of fuel, it just cuts off.
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
To me it drops too fast to be a fuel issue. I also don't hear the motor trying to stay running like when it runs out of fuel, it just cuts off.
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Also at 1000 - 1500 RPM it is not really on the idle part of the carb so adjusting the idle mix would do nothing.
You are right as a easy check if fuel issue, pop the filter off look down the carb and move the throttle.
If he sees fuel squirt it is not a fuel issue and needs to look else where for the issue.
I still like to know what he is running for IGN and a carb.
Dave ----
Engine RPM's have no bearing if he is on the idle circuit or not throttle blade position does. And no when you starve for fuel you will start getting RPM fluctuations this is especially true with annular boosters as air flow becomes erratic in the booster. Again this is most likely in part due to idle mix settings. And since this an aftermarket carb it begs the question was the idle mix ever set up...
Thread Starter
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Mountain Pass
Joined: Nov 2019
Posts: 142
Likes: 0
Engine RPM's have no bearing if he is on the idle circuit or not throttle blade position does. And no when you starve for fuel you will start getting RPM fluctuations this is especially true with annular boosters as air flow becomes erratic in the booster. Again this is most likely in part due to idle mix settings. And since this an aftermarket carb it begs the question was the idle mix ever set up...
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Also, check to be sure the choke is fully coming off on hot engine, and closing on a cold engine.
It sounds like the carb just needs set up properly.