Detroit 3-53 help? Advice?

Got a old skidder with a 3-53, previous
owner said he had it rebuilt and re man
injectors..it runs but just don't rev up
hardly at all.. so if downloaded manuals and
got the tool, adjusted valves, adjusted
injectors...s50 injectors btw..prev owner
said there bigger injectoes... any how..same
storie..wont hardly rev high, but now wants
to idle high, so went in and re checked all
the valves, Injectors, and this time ran the
rack also...even had a guy help, still same
storie..so we took the govner top off
adjusted it per book, now it won't idle at
all, noticed a fork in there looked to have
some slop... Well my question is ..can
someone explain what the buffer screw
does..how to adjust the gap, and the no load
screw...iv done it all per book but still
won't rev high or idle . It's driving me
crazy

If you have the manuals, all those questions should be answered. Try finding a standard Detroit operator's manual for a 3-53, detailed governor adjustment/ engine tune-up instructions found in there. Off the top of my head I would say you have bent/ binding gov. linkage, binding control tube, or a stiff rack in one of the injectors. What you need to do before you do anything else is to verify operation of the emergency shut-down, in case something goes further wrong.

If it's turbo charged, it might have a fuel modulator. This needs to be disconnected while setting the injectors. Also this assembly could be damaged, causing the symptoms you describe.

Blower fed

The shut down is working and is there if needed, don't seems like anything is sticking, just this govner is eather wore out or not adjusted right

Since you have to have the governor cover off to set governor gap, will it rev up when moving the control tube by hand?

No, it's not worn out, we're just missing something simple here. I should add here that the governor/injector action should be smooth and operate freely. Did it run after the guy rebuilt it? When did all this trouble start?

Yes, revs up great. Fast also by hand

It's been running, but since iv owned it it's never r illy raved up high, I have a lot of play in the fork that attaches to the throttle rod and the govner rod..and if I set the buffer screw per book, 5/8 From locknut it wants to stay raved up and not idle down... also. When setting gap, book calls for it to be .006 from spring cap to plunger, one book says at 1100 rpm other said not running, well how is this done when the idle screw also controls that gap to? What am I not understanding?

Just a long shot, but check the fittings in the cylinder head for the fuel lines. These engines use a restricted fitting in the return line to maintain adequate fuel pressure. If this fitting was replaced or relocated during the rebuild, it could cause similar symptoms due to low fuel pressure. I have seen this before. It has also been over 25 yrs since I touched a two stroke Detroit FWIW.

The instructions that say you can set the gov. gap with engine stopped are referring to the Dual Weight Limiting Speed (road governor), which requires a wedge-shaped tool with a long handle to hold the low-speed weights in while adjusting the gap. I went all through my Genuine GM 53 instructions and never once saw the gov. gap set with the engine off. However, the 71 books DO show this, together with the genuine GM governor wedge; which leads me to wonder if the instructions you have are generalizing the adjustments for all Detroit governors, which will not work.
When the book tells you to back out the buffer screw to 5/8" above the locknut, this is just a generalization, a preliminary adjustment so the governor adjusting procedure can begin. If it's still in the way, back it out a little more until you can check the gov.gap. The buffer screw is set for good and all as one of the last steps in the process. There is a light spring sticking out of the end of it, which lightly contacts the differential lever (the forked thing). It's purpose is to hold the gov. linkage steady at low idle, so it doesn't sit there going rrrrrrRRRRRRRRrrrrrrrrrRRRRRRRRrrrrrrrrRRRRRRRRRR (get the idea?)
I should add at this point that there are different governors for the same engine family and you need specific instructions for each. There is the D.W.L.S mentioned above, or the Single Weight Variable Speed (open linkage) or the S.W.V.S. (enclosed linkage). (These last two are off-road governors) All styles are identified plainly by a tag on the side of the governor. Another easy way is the cover. Two levers in the cover, D.W.L.S. One lever in the cover and the other on the end of the high-speed spring, S.W.V.S.
Setting the gov.gap is not an exact science, there is just no way to hold the engine perfectly steady. For instance, if you have it at 1000 RPM with the gov. gap at .006", just the air compressor kicking on will alter the engine RPM enough to open the gap. Just do the best you can, it'll be fine.

Fritz had offered some good advice on things to check. Since you say it's never reved very high, have you checked the shims in the governor? The number of shims on the high speed spring will limit the highest RPM available.

All of this stuff should be in the manual you have. If not, poke the link below and it will take you to a manual page where this is explained. You should also be able to move forward and backwards in the 'book' to see the full adjustment procedure.

I've had to adjust many old Detroits over the years when others had been messing with them and didn't know what they were doing. In once instance the engine had never reved to speed, just as you say yours is doing. When I finally got everything adjusted properly, my customer about had a heart attack when it hit what he thought was supposed to be wide open for that application, and I showed him it still had nearly 500 RPM left to go. He thought the engine was about to blow apart and jump out of the machine, but it was actually just on spec for a change.

Given that most people either mess with the shims without knowing what they are doing, lose them and don't realize it, or whatever, this just might be what has happened with the one you've got.

Good luck, and let us know what you figure out.
Poke here

Hello,
I am new to this forum and need advice on 3-53 so thought I would add to this thread. We are doing a research project to try and run an engine on syngas from a biochar plant we have developed. I have chosen to try a Detroit 2 stroke due to lack of inlet valves to clog up with any dirty gas and have purchased a second hand 3-53. As we will be converting the engine to spark ignition and we still need a compression ratio of around the standard detroit - 17:1 to suit the slow burning gas - but the engine we bought is the "N" version with a higher 21:1 compression.

My question is - can I fit the standard engine pistons (not the "N" version) into the engine to reduce the compression back to the standard engine 17:1? We are removing all the fuel system so I don't care about differences in injectors etc. Appreciate your time.

chad sheppeard said:

Hello,
I am new to this forum and need advice on 3-53 so thought I would add to this thread. We are doing a research project to try and run an engine on syngas from a biochar plant we have developed. I have chosen to try a Detroit 2 stroke due to lack of inlet valves to clog up with any dirty gas and have purchased a second hand 3-53. As we will be converting the engine to spark ignition and we still need a compression ratio of around the standard detroit - 17:1 to suit the slow burning gas - but the engine we bought is the "N" version with a higher 21:1 compression.

My question is - can I fit the standard engine pistons (not the "N" version) into the engine to reduce the compression back to the standard engine 17:1? We are removing all the fuel system so I don't care about differences in injectors etc. Appreciate your time.

Click to expand...

Short answer is yes, but I am not sure if sleeves are the same. You will likely be changing sleeves anyway so probably mute point. We went the other way and put the N kit in a standard 17:1

You just wait until the thread gestapo finds out you contributed to a 6 year old post. You in big trouble man.

tom upton said:

Short answer is yes, but I am not sure if sleeves are the same. You will likely be changing sleeves anyway so probably mute point. We went the other way and put the N kit in a standard 17:1

Click to expand...

Thanks, appreciate your reply.

chad sheppeard said:

Hello,
I am new to this forum and need advice on 3-53 so thought I would add to this thread. We are doing a research project to try and run an engine on syngas from a biochar plant we have developed. I have chosen to try a Detroit 2 stroke due to lack of inlet valves to clog up with any dirty gas and have purchased a second hand 3-53. As we will be converting the engine to spark ignition and we still need a compression ratio of around the standard detroit - 17:1 to suit the slow burning gas - but the engine we bought is the "N" version with a higher 21:1 compression.

My question is - can I fit the standard engine pistons (not the "N" version) into the engine to reduce the compression back to the standard engine 17:1? We are removing all the fuel system so I don't care about differences in injectors etc. Appreciate your time.

Click to expand...

I don’t know what syngas is, but the statement about clogging the intake valves is confusing. The only way to get this gas in is through the blower… if deposits are going to form on the intake valves, there is like zero tolerance for this to occur in a high precision device like a blower… which is going to be spinning at about 4.5K rpm.
Likewise for the ports in the liners… an intake valve is much bigger and has the potential to shake off deposits, but those little air ports? They could be blocked nearly completely.

Fritz Maurer said:

I don’t know what syngas is, but the statement about clogging the intake valves is confusing. The only way to get this gas in is through the blower… if deposits are going to form on the intake valves, there is like zero tolerance for this to occur in a high precision device like a blower… which is going to be spinning at about 4.5K rpm.
Likewise for the ports in the liners… an intake valve is much bigger and has the potential to shake off deposits, but those little air ports? They could be blocked nearly completely.

Click to expand...

Thanks Fritz,

Syngas is a weak gas made through the process of making charcoal (typical CO, Methane, Hydrogen but diluted with Nitrogen and CO2), ours is fairly clean but previous attempts of others running 4 stroke engines it is very common to block at the intake valves - this is because the air speeds up and cools down as it goes past this area and condenses any liquids (tar) in the gas out at that point.

I will not be running the blower on the engine as we have supply from a blower in our process (actually a roots style blower) that we can control flow and pressure and we will be mixing and preheating the gas and air a little before entering the engine so it does not condense anything. The cross sectional area of the ports in the detroit cylinders add up to a much large cross sectional surface area than typical inlet valves so the gas velocity is slower than the inlet valve pathway on a normal 4-stroke engine.
Hope that makes sense - thanks for your interest and comments.
Chad

chad sheppeard said:

Thanks Fritz,

Syngas is a weak gas made through the process of making charcoal (typical CO, Methane, Hydrogen but diluted with Nitrogen and CO2), ours is fairly clean but previous attempts of others running 4 stroke engines it is very common to block at the intake valves - this is because the air speeds up and cools down as it goes past this area and condenses any liquids (tar) in the gas out at that point.

I will not be running the blower on the engine as we have supply from a blower in our process (actually a roots style blower) that we can control flow and pressure and we will be mixing and preheating the gas and air a little before entering the engine so it does not condense anything. The cross sectional area of the ports in the detroit cylinders add up to a much large cross sectional surface area than typical inlet valves so the gas velocity is slower than the inlet valve pathway on a normal 4-stroke engine.
Hope that makes sense - thanks for your interest and comments.
Chad

Click to expand...

I know what you’re talking about now. I build charcoal kilns for cuyahoga lump charcoal and watched the process. When it goes into gasify mode , that soot makes an insane mess. We pipe the gas into the firebox so it is self-powered part of the time.
In your opinion…. Is it because the gas pipes are hanging out in the air, being cooled, that we have such a soot problem? Preheating is the answer?
We have just accepted the problem and made the pipes come apart easily for cleaning.

Fritz Maurer said:

I know what you’re talking about now. I build charcoal kilns for cuyahoga lump charcoal and watched the process. When it goes into gasify mode , that soot makes an insane mess. We pipe the gas into the firebox so it is self-powered part of the time.
In your opinion…. Is it because the gas pipes are hanging out in the air, being cooled, that we have such a soot problem? Preheating is the answer?
We have just accepted the problem and made the pipes come apart easily for cleaning.

Click to expand...

During the process of making charcoal everything comes out of the wood as a gas (leaving the solid carbon) - this means all the water vapour, hydrocarbons like oils and tars , acids etc these compounds will then condense out of gas at different temperatures, so tars are typically around 250-350C. You can either trap them as they come off and cool through water trap, or maybe lagging the pipe to fire box will help keep the temperature up so the gas doesn’t cool as much in the pipe.