79 chrysler 140 won't start

bman1bpm

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Jul 19, 2004
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450
Motor wouln't start at the ramp today. It would start in fast idle but only run for about 30 seconds and then it would stall. Its been running worse and worse over my past 4 trips out. Last trip it would die out at idle but if I started it and put it in gear real fast it would go.

Checked compression once I got home
1-150
2-148
3-145
4-150
 

Frank Acampora

Supreme Mariner
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Jan 19, 2007
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12,004
Re: 79 chrysler 140 won't start

FIRST, Change the plugs!

You have twin fuel pumps in series, so check both for a bad diaphragm. Then check the electronics to be certain you are getting consistant spark.

Check to see if the idle stop nut has loosened and the screw is backing out, lowering the idle to the point where the engine will not run reliably in neutral. be certain the timing has not changed. If you have a distributor, check the cap, wiring, and rotor.

If everything checks out, raise the idle speed.
 

bman1bpm

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Re: 79 chrysler 140 won't start

I actually was on a brand new set of plugs, had just changed them before I went out. I put my old ones back in when I got home, ran better, but still not right.
I went to the auto parts store to buy some fuel line to install my water separating fuel filter, guy at the counter told me that 3 other people came in today with the same problem! Thinking it might be bad gas, so I'm going to drain the tank and see if some new fuel will help. I already took off the carbs and cleaned them just in case. Will also check the distributor, haven't pulled that cap off in a few years.
 

bman1bpm

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Re: 79 chrysler 140 won't start

Spark is good, checked timing, its at 30 degrees.
Checked fuel pumps, one was good, one was tearing in two places...odd because they've only a few months old, but replaced both.

Drained old gas, put in new gas, synched carbs.

Now I've run into the same problem I've had since I got it, I can either idle at the correct RPMs and lose top end RPMs, or idle at 2000, and have it run wide open real well. Kinda stumped on how to adjust properly.
 

sho3boater

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Re: 79 chrysler 140 won't start

Adjust the throttle cable for full opening of carbs. The timing should be full advanced long before that. If not that then the control could have an issue if you don't have enough cable travel to get idle and wot. Idle is set on the motor not the cable.
 

bman1bpm

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450
Re: 79 chrysler 140 won't start

When the cable it set for full carb opening, in neutral they don't close properly.. and I get the 2000 rpm idle, do you think I need a new throttle cable?
 

Frank Acampora

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Jan 19, 2007
Messages
12,004
Re: 79 chrysler 140 won't start

Unless the cable is so worn that it doesn't function, is kinked, or is too short so it is binding, you don't need a new one. It is best to have a loop of cable in the spashwell to prevent binding.

You connect the throttle cable. With the control in neutral, adjust the throttle cam (using the two black plastic ball end fittings) so the line is centered on the carb roller.

Remove the fitting at the tower to adjust; if you remove the one on the cam, you run the risk of bending the cam. But adjust both fittings equally. Do not tighten the jam nuts excessively; this may crack the black plastic fittings.

If there are two lines on the cam, close together, center the roller between them. The roller is mounted on an eccentric screw. Loosen the nut and turn the screw until the roller JUST touches the cam. The bottom carb is now fully closed. THIS IS ONLY THE STARTING POINT AND WILL CHANGE. Loosen the carb link and let the top carb snap shut, then tighten the screw again. Now, both carbs will open approximately the same amount for a given throttle setting. Note that there is some play and you can tighten the bar a bit upward so the top carb opens at the same time as the bottom one. Otherwise, it will open slightly less than the bottom.

Then you adjust the two black plastic ball end link so the carbs open fully at wide open throttle. With the (black plastic stop) hard against the block, the butterflies should be level or close to it--a slight difference from horizontal is not significant. Don't go crazy trying to get them exact.

Next, you return the throttle handle to neutral and with the warm engine running in the water in forward gear, adjust the idle stop screw on the bottom of the tower for proper idle speed. Note that the line on the cam will usually be slightly below the carb roller, giving a very slight carb opening.

Note that each time you remove the carbs, the gaskets will compress differently and the carbs will set on the studs differently, SO The procedure MUST be done anytime the carbs are removed and replaced.

NOW: The throttle cable quick connect fitting should be the large one with the spring loaded center. The center should protrude, about 1/4 inch more than when fully retracted, in neutral. This gives the necessary shift travel BEFORE the throttles begin to open. If it is not protruding, screw it further on the cable until it does.

If you have a distributor, check the belt tension. Too tight and you will have trouble shifting OR the distributor will not return to proper timing when the throttle is returned to neutral. This will give advanced timing which will give a very high idle speed. Too loose and timing will wander a bit.

The distributor belt should deflect using a steel .010 feeler gauge pointed into the center like a finger. The belt should deflect 1/8 to 3/16 inch before the feeler gauge bends.

EDIT: BTW: Check the plastic bushing the cam is mounted on. It should be snug, not sloppy with the nut just touching it, and the hole should not be excessively worn.
 

bman1bpm

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Re: 79 chrysler 140 won't start

wow those instructions are significantly better than those from clymer. I'll give it a shot! thanks!
 

bman1bpm

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Re: 79 chrysler 140 won't start

I went through the procedure frank listed.
1) Both my shift and throttle cable quick disconnects are identical, is this a problem?
2) It seems like my my throttle cable just doesn't have enough movement. If the idle screw is pegged against the block, when I put it in full throttle, it only moves to about 3/4 throttle even though my control box is at full throttle. There is a long dead spot, when I move my control box from neutral to 1/2 throttle the cable has no movement, then from 1/2 throttle to wide open it moves.
 

bman1bpm

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Jul 19, 2004
Messages
450
Re: 79 chrysler 140 won't start

Ok, got a new throttle cable(a few weeks back) installed it and got the boat out again, it had been a while, I'm back in school again. The new throttle cable did the trick. I now can adjust the throttle smoothly and it goes all the way from a nice idle at 800-900 rpms to a WOT of 5100 rpms..guess my prop isn't quite right but, minor details.
 
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