151A2 Starting problems

[Rangemaster]

I'm trying to get my 151A2 fired up so I can use it in the 4th of July parade in town. It's been sitting for awhile. Got new batteries, starter turns fine, fuel pump is working, but I have no fire. It doesn't even cough with starter fluid. Is there a good way to troubleshoot the ignition system?

[markrdje]

I would check for spark to the spark plugs
mark

[Rangemaster]

Yeah, that one was out of my capabilities being alone. On my to do list. Is there a block of fuses to check?

[Fil Bonica]

Send the jeep freight prepaid and I'll take it of your hands !!!
Seriously, take a plug off and have someone turn it over while you hold the ignition wire away from a metal surface:":
If no spark start looking closer.

Fil Bonica

[Rickf]

Does it have points or electronic ignition? Could be dirty points. No fuses on a M-151. An A2 has only two circuit breakers behind the dash to the left of the instrument panel. This would not usually be an issue unless you have crumbling insulation on your wires. Pull the wire off of the distributor inlet and see if you have 24 volts with the switch on. If yes then the problem lies in the distributor

[Rangemaster]

Thanks. I might have to check the dash fuses, the wiring looks to be a mess.

[Rickf]

The breakers are self resetting so there is nothing to check, unless you have a bad breaker. You cannot tell by looking at them. Check voltage in and out to find out if it is passing voltage.

[Kurt Lesser]

If you have +24 volts on the connector going into the distributor when the ignition switch is on things are good to that point. Use an ohmmeter on a resistance scale and measure between the center pin on the distributor to the distributor case. This checks the input capacitor, something that people tend to overlook because it's a part of the input connector. On a resistance scale you should see the reading drop and then start to increase as the capacitor charges. It's only the voltage used by the ohmmeter itself so there's no worry about any high voltage being present. I recently worked on a 151 where the owner had replaced the coil and had shorted the internal cable from the cap to the ignition module and this test would show that too. There are 3 different types of ignition configurations. One is the old Kettering style ignition with a set of breaker points opened and closed by the distributor cam lobes. They can pit, become resistive, or get out of adjust in addition to getting oil soaked. Anytime the points got changed you were supposed to check the DWELL with a dwell meter that verified that the point gap was set properly. The 2 types of electronic ignitions are inductive and photoelectric, both of which use sealed modules that can only be tested by replacing them.

Naturally the coil itself can fail and they have a bad habit of doing so. Most of the aftermarket coils aren't very reliable, stay away from anything with a chromed case. One of the most amazing things about these coils is that after the millions of them that were made over the decades for all of the M series vehicles and the thousands of them removed from scrapped 151's they tend to be fairly scarce and prices have been rising steadily over the years. It's one part you should always have a spare on hand.

Good luck

[Rangemaster]

Well, that certainly gives me a lot to go on. Time to break out the multimeter and get busy. Looks like I'll have time to order a new distributor in time if that's the case.

[W. Winget]

Thanks. I might have to check the dash fuses, the wiring looks to be a mess.

It's funny to see you type this when your list of vehicles below your signature has ZERO fuses in any of them.

Like the man said, check for voltage. Your 24V M37 Distributor may have a coil that fits in the MUTT distributor, only the number of cylinders are different in the distributor there, but I'm not certain of the length.

And very likely if it's been sitting that long your carburetor is toast from ethanol fuel gumming the works up. MUTTs don't like ethanol after as little as two weeks of sitting from what I've seen.

Good hunting, at least your early. W. Winget

[Rangemaster]

I am aware. The previous owner seemed to like adding inline barrel fuses to the wiring he replaced like it was his religion. All wrapped in copious amounts of electrical tape to conceal them.

The M37 is hours away at our ranch, but that's good to know.

[Kurt Lesser]

The coil used in all the M series vehicles has been the same since the 1950's. That's why it's so strange there's a shortage of them.

[Rickf]

The coil used in all the M series vehicles has been the same since the 1950's. That's why it's so strange there's a shortage of them.

Or maybe that is why there is a shortage of them. When did they stop making them? I know the last contract was filled by overseas contractors, hence the shiny coils in the proper packaging with the proper parts with them.