1978 F150ranger issue?
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Junior Member
Joined: Nov 2008
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From: Minnesota
1978 F150ranger issue?
I have a 1978 F150 Ranger 4x4 (351M)
I bought it about a month ago, but all of a sudden it has started something I am not familiar with,
The Engine sometimes, run at about, 500-800 Rmp's, and sometimes it runs at 1300-1700 Rpm's, but usually idles at about 1100Rpm's.
I think it's the carb but I am not certain.
If anyone knows about this type of motor I would love for the help.
I don't want to go out and buy anything not needed.
another note. If I rev the Engine up to about 3k-4k...basically pin it for a second or 2 it equals out and idles at 1100Rpm's, So I have no clue.
I bought it about a month ago, but all of a sudden it has started something I am not familiar with,
The Engine sometimes, run at about, 500-800 Rmp's, and sometimes it runs at 1300-1700 Rpm's, but usually idles at about 1100Rpm's.
I think it's the carb but I am not certain.
If anyone knows about this type of motor I would love for the help.
I don't want to go out and buy anything not needed.
another note. If I rev the Engine up to about 3k-4k...basically pin it for a second or 2 it equals out and idles at 1100Rpm's, So I have no clue.
Senior Member
Joined: Feb 2008
Posts: 4,658
Likes: 28
From: Henderson, NV.
Good morning and welcome to the forum.
A couple things come to memory, lets talk carbuation first. The two barrell that is on there is as easy to work on as they come. Biggest concern I remember, is the power valve. People have a tendency to over torque it. Using the instruction sheet provided with the overhaul kit, you shouldn't have a problem. Another overworked or overadjusted item is the choke mechanism. Align the mark on the cap to the mark called out in the instructions. Might be index or 3 rich. Rich is the direction when turning the cap that tends to close the choke plate. A very important item to check is the choke unloader. Hold throttle full open, how far is the plate open, measuring at the bottom of the plate. Again use directions.
A very common concern for that engine is the intake gaskets. Go to the parts store and look at one. Unless they have change the design over the years, you will see its a metal pan with compression ridges around the valve openings. If you change the intake gasket, you will quickly learn an interesting point about the 351M engine. No water is in the intake manifold. Only engine that I know of that is made that way.
A couple things come to memory, lets talk carbuation first. The two barrell that is on there is as easy to work on as they come. Biggest concern I remember, is the power valve. People have a tendency to over torque it. Using the instruction sheet provided with the overhaul kit, you shouldn't have a problem. Another overworked or overadjusted item is the choke mechanism. Align the mark on the cap to the mark called out in the instructions. Might be index or 3 rich. Rich is the direction when turning the cap that tends to close the choke plate. A very important item to check is the choke unloader. Hold throttle full open, how far is the plate open, measuring at the bottom of the plate. Again use directions.
A very common concern for that engine is the intake gaskets. Go to the parts store and look at one. Unless they have change the design over the years, you will see its a metal pan with compression ridges around the valve openings. If you change the intake gasket, you will quickly learn an interesting point about the 351M engine. No water is in the intake manifold. Only engine that I know of that is made that way.
Think it'll start?
Joined: Dec 2008
Posts: 13
Likes: 0
From: Fay, NC
Good morning and welcome to the forum.
A couple things come to memory, lets talk carbuation first. The two barrell that is on there is as easy to work on as they come. Biggest concern I remember, is the power valve. People have a tendency to over torque it. Using the instruction sheet provided with the overhaul kit, you shouldn't have a problem. Another overworked or overadjusted item is the choke mechanism. Align the mark on the cap to the mark called out in the instructions. Might be index or 3 rich. Rich is the direction when turning the cap that tends to close the choke plate. A very important item to check is the choke unloader. Hold throttle full open, how far is the plate open, measuring at the bottom of the plate. Again use directions.
A very common concern for that engine is the intake gaskets. Go to the parts store and look at one. Unless they have change the design over the years, you will see its a metal pan with compression ridges around the valve openings. If you change the intake gasket, you will quickly learn an interesting point about the 351M engine. No water is in the intake manifold. Only engine that I know of that is made that way.
A couple things come to memory, lets talk carbuation first. The two barrell that is on there is as easy to work on as they come. Biggest concern I remember, is the power valve. People have a tendency to over torque it. Using the instruction sheet provided with the overhaul kit, you shouldn't have a problem. Another overworked or overadjusted item is the choke mechanism. Align the mark on the cap to the mark called out in the instructions. Might be index or 3 rich. Rich is the direction when turning the cap that tends to close the choke plate. A very important item to check is the choke unloader. Hold throttle full open, how far is the plate open, measuring at the bottom of the plate. Again use directions.
A very common concern for that engine is the intake gaskets. Go to the parts store and look at one. Unless they have change the design over the years, you will see its a metal pan with compression ridges around the valve openings. If you change the intake gasket, you will quickly learn an interesting point about the 351M engine. No water is in the intake manifold. Only engine that I know of that is made that way.
Last edited by 460WHAT?; Dec 26, 2008 at 10:52 AM. Reason: spelling