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MEP-016A 4A032 Keeps Shutting Down

nezwick

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I picked up a 1973 MEP-016A-II at an auction the other day in non-running condition, mostly just to "play" with and see if I could bring it back to life. It only has 40 hours on the clock, and the hour meter does work. It has a Teledyne 4A032 with a Marvel/Schebler HMC-10 carburetor (with adjustable jets!).

The seller seemed to think it was locked up; turns out the cylinders had been filled with clean oil years ago for long-term storage (way, way too much oil) and it just had built up too much compression to turn over.

Anyway, it needed completely gone through. Points and spark plug cleaning, purging ancient varnished gasoline from all the fuel lines, carb, and tank, oil change, etc. The usual stuff.

I have done a bunch of reading on this setup and the biggest complaint seems to be the float in the carb swelling up and sticking due to ethanol. My float appears to be in perfect factory condition, just discolored. I tested it by floating it in water and it does not sink. When in the carb, it moves the needle in and out very smoothly, does not drag on the sides, and does its job shutting off fuel flow when needed. The Viton tip needle appears fine.

I did eventually get the gen set to start and run, governor adjusted to 3600-ish, and was able to verify electrical output using a multimeter and a couple of lights and power tools. Was pretty proud of this accomplishment except for one major problem:


No matter what, it will only stay running for between 1 and 3 minutes. When it runs, it runs beautifully. Starts right up and sounds great. No oil burning, no misses or stumbles, exhaust clear.

After going through everything I could possibly think to go through, twice and three times, and disassembling the carburetor at least 10-15 times, I'm now at a complete loss. The gas is fresh ethanol-free 91 from our farm tank, oil at the correct level, plug gap correct, points clean, carburetor needles adjusted exactly to spec.

So I thought, maybe it's "smart" and will shut itself down after a specified period of time if no load is detected. Connected a shop light and a grinder and let them run. No difference.

What could I be missing here?
 

Rich Mc

Registered
Re: MEP-016A 4A032 keeps shutting down

Does the engine have ignition points or is it upgraded to the electronic ignition?

(Just reread your post you have points.)


You might considering upgrading to the electronic ignition. It is available at Saturn Surplus and other military parts suppliers.
 

nezwick

Registered
Re: MEP-016A 4A032 keeps shutting down

Hmm, sounds like an ignition related issue to you? I was too focused on fuel problems to actually consider that. Is it possible the ignition coils are getting heat-soaked and cutting out? It's been very hot outside the past few days and the engine itself does get quite hot to the touch.

I was looking at the electronic ignition conversion set on eBay earlier, but not too seriously. I don't mind points ignition, but would gladly to the conversion if it would solve the problem.

Any troubleshooting steps I can follow to isolate the ignition issue vs. fuel?


My fuel pump does not have the primer lever, but if I disconnect the line from the carb and give the rope a few pulls, it seems to be pumping plenty of gas. Also, it has enough strength to draw the gas up through the lower tank and all the plumbing so I called it good.
 

Rich Mc

Registered
when its running and the engine starts to die spray some starting fluid into the carb, if it continues to die its probably ignition related.
 

nezwick

Registered
Well I think I've made a bit of progress.

To answer your question, yes it will keep running if starting fluid is sprayed into the intake after it starts to die.


I continued chasing fuel delivery problems today. I found a brass strainer screen that I had missed before, and it was almost completely plugged. Said screen was located right inside where the fuel elbow threads into the side of the carb bowl. I had not removed this elbow before because I could blow compressed air through and figured it was unobstructed. Turns out air could get through but sufficient gasoline could not. The screen is not shown in the TM so I wasn't expecting it there.

Anyway, I'm now getting plenty of gas into the carb - too much actually. It will run continuously without dying but it wants to run rich and I can't get it leaned out to where I want it.

I had previously adjusted the float level to 1/16 inch ABOVE level with the top of the fuel bowl, per some instructions that I ran across on the internet. This setting now caused the carb to flood and start spilling gas out. So I adjusted to about 1/16 BELOW level and it does not spill out, but still runs rich.

The float still has perfect freedom of movement within the bowl and is not damaged.

Should I adjust the float level even lower now? The weirdest thing to me is that even if I turn the main jet needle completely closed, the engine will continue to run (rich). This tells me that somewhere the gas is able to bypass the needle completely.
 

Rich Mc

Registered
Paste this thread into the search box, it may give you some answers/ideas,


2A016 Genset Carburetor Guidence Needed
 

nezwick

Registered
Thanks, I do remember reading that thread a couple days ago and that’s where I learned to set the float level just a bit under the top of the bowl.

I guess I forgot to mention in my original post that I did already make new homemade gaskets for the bowl and for the “center post” because they were both rotten. I used water pump gasket paper that I had in the shop. I have some cork too but it’s too thick for this application.

I may still try to lower the float level just a small amount more.

I may actually have the Tecumseh needle/seat parts here in my parts bin. That’s worth a try too, I suppose.
 

s100

Registered
I just bought a new carburetor body gasket from Saturn Surplus. I think it was $2. Maybe you are a lot better with an X-Acto knife than I am (doesn't take much) and your gasket is perfect but I know mine would not be and it is important to have the gasket right to make the carburetor happy. Two bucks for a crummy little gasket seems kinda extortionate but when I think about all the work involved with trying to make one it's downright reasonable.
 

s100

Registered
Rich Mc, Saturn only has the main body gasket. And I was wrong, it is $3.50 not $2. Still, I'd prefer that to fooling around for hours making one.
 

nezwick

Registered
Well I think I have solved this issue!

I took the carb apart one more time, mainly to assess my homemade gaskets since you mentioned that could be something not quite right.

What I found was, a crack in the carburetor. I had missed this so many other times because it was so small and pretty much just looked like a casting flaw.

My best guess is some fool screwed in the main jet needle way too far and caused stress to the metal around the orifice where the needle tip goes. It was about 3/32" long running from the orifice upwards.

I had some gasoline resistant sealant material laying around so I gave the whole thing another thorough cleaning and then applied the sealant to the crack. Let it cure for about a half hour and then reassembled. And guess what, it runs perfectly now. No stalling, no rich condition, and needle valves actually work.

Ran nicely for about 30 minutes before I had to quit and come inside.

Only time will tell if the repair will actually last, or if I'll have to re-do it with JB weld or some sort of aluminum solder. But for now I'm pretty happy with that result.



On to the next question:

How do I tell if the thing is actually running at 3600 RPM? It sounds good by ear but my tachometer needs to be able to sense the impulses of the spark plug wires, and the shielded wires on this unit prevent that. Is there another wire I can connect the tach to?

I know it's supposed to make 60 Hz at 3600 RPM, but no matter how fast I run the engine, I can't get up higher than 58-59 Hz (unloaded). Ideally it should be 61-62 Hz unloaded and 60 Hz loaded. This might be an issue with the Hz gauge, but I can't figure out how to get my multimeter to display Hz to compare the results.
 

miltruck

Registered
I just posted on another thread about the dangers of using ethanol gas in these engines, so I won't repeat myself.

Contact Saturn Surplus (by phone) and check with them about gasket kits. I know they don't have floats in stock and last time I looked the replacement carbs were super expensive but they may have gasket sets. If I recall correctly, the jet well gasket is flat and not so thick, but a small o-ring may work.

Forgot to add:
Harbor Freight sells a non-contact RPM meter for not much money. Very handy for all types of engines/motors/driven machinery that do not have a gauge or meter on them.

I just got Hz/voltage panel mount meter from a vender on E-bay for about $25 shipped. He is in Georgia and sells all sizes of gen set heads and parts. Use this one on a 20Kw 2-53 Detroit that has a variable throttle so loaded running Hz is @ 60 +/-and no load is 61-62 HZ or so. Seems to work fine.
 

nezwick

Registered
Thanks for the info about the no-contact RPM meter and source for gauges. I suppose I should probably get a better multimeter that can read Hz if I plan on doing any more gen sets.

And yeah, I would never run ethanol gas in this, or any of our small engines for that matter. One of the benefits of having a farm tank, we just get bulk deliveries of ethanol free 91. There are no gas stations within 25 miles of me that sell ethanol free at the pumps. I think I have called every single one.
 
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