The arm that pushes the governor rod down needs to be bent up, slightly.

Walt Conner

Thanks Walt, Is there some sort of device that can be made to check the gov? I don't quite understand it totally but it says in the manual to depress the throttle shaft while using the special gage. The gov should be 1/16"-3/32" between top of gov rod and bottom of of the lever.
Is there some diferance in the gov spring? The manual says there were different colors for different speeds. My kit came with one and thats all I know about it. I don't remember any color.
BTW, This machine only has one speed no variable speed lever.

Thanks, Neal

There is a gage but I have never had or used one. I set them so that the carb butterfly lever sets about at the 11 o'clock position when the engine is stopped, perhaps a little past. If you go too far, the butterfly lever will "over center" and stick. The position I mentioned usually makes the engine run about the right speed. Yes, there are, some have said, 3 different springs. I am only aware of 2, one for engines with speed control and one for engines without speed control in lawnmowers. Perhaps the others are for other applications. I would say your kit probably came with one for those without speed control but IF you can not get the engine to run fast enough after making the setting as I described, perhaps you do not have the right spring in which case I would send you one for postage.

Also, there is a difference in the length of the governor rod from the carb butterfly lever to the governor arm between D400 engines and D600 engines.

Walt Conner

Walt, thanks for your time. I appreciate it sincerely. I can do "f" series engines blindfolded but these D-400's sure get me most of the time.
One more Question. What RPM should you consider ideal for a single speed D-400 with upper belt drive?

BTW, I removed the gov system to take a look at the new spring and sure enough its green which says 2500 RPM in the mechanics handbook. Is this right for D-400 engines to run? I guess I can't get over how slow it seems.

I'll do the adjustment tomorrow and I'll let ya know.

Thanks a million, Neal

3200 is pretty universal for Lawn Boy mowers. The "adjustment" will do no good if it is the wrong spring.

Walt Conner

Well, this thing just pitter putters around. I don't get it. It wants to take off but the gov I think won't let it. The carb is imaculate clean, the coil and plug are good, set w/business card, the points are gapped and functioning, The seals are new and in place (not leaking either) reed is new, gaskets new, proper torqed cylinder and hardware, clean exhaust ports and muffler, rings and piston excellent cond, good compression, what else am I missing??
It starts fine then goes through this pitter putter stuff and smokes like crazy. I've tried two different D-400 carbs, one that came with it and a modular carb from a newer D-411 that I have. (Which ran slow also) I switched coils tonight also thinking the coil and plug may have been going bad, no beans.

I'm not sure what I'm missing here. Can some one give me some other ideas? I can live with the slow running but now I need to get her running proper again.

Thanks, Neal

"pitter putter stuff and smokes like crazy"

This sounds to me like it is running terribly rich. Have you adjusted the mixture needles, High and Low? Have you taken your finger and pushed the throttle lever/governor rod up when the mower is running?

CAUTION; Be VERY, VERY careful to keep your fingers, etc. out from under the deck, away from the blade. I knew a very experienced tech who got his hand seriously injured this way.

Walt Conner

Use the metal carburetor, Has it been rebuilt ? What is the condition and setting of the float? Is the throttle shaft worn and overly loose?A quick check for governor adjustment is to look at the position of the throttle lever arm when the engine is not running., it should be at a 45 degree angle indicating the throttle disc is in the wide open position. With a properly assembled and set governor it all falls on the carburetor to supply a steady flow of fuel. Preset the main needle to about 2-3 turns open.

Guys, the throttle disc seems fine to me, no excessive play. It is sitting at a 45 deg angle. I switched points this afternoon as well a different gov system from another d-400. No change.
It is using loads of gas in the short trials I've run it. The only thing I can think to try next is a different float but that one is new and set at the 15/32 level the manual calls for. And the modular carb had no change either.

Can I use a metal carb from a D-600 that I use every week? I know this carb is good as I use it often. I'm just not sure if there is some sort of difference in the way they will function on different machines.

Thanks, Neal

Are you sure the muffler is not plugged? You said you just did a complete rebuild so I am assuming the exhaust ports are clean.

You can use the D-600 carb, may have to switch reed plate also, you will have to do something about the primer also, the D400 and D600 use different lengths governor rods as I said before.

Walt Conner

Thanks Walt and Mike72, I had to basically walk away from this machine for a little while. It becomes a obsession if I don't leave it alone for a break. I swear I could stand there at my w/bench for hours thinking and trying stuff.

Walt, I'm sure the exhaust is clean, ports are fully open and I totally cleaned the muffler. Later today I'll recheck the float and even try the d-600 carb.

Once again, many thanks to you guys on here.

Neal

It sounds to me as if the carb is "loading up" the engine with a rich fuel mixture....
The float may be upside down....or the brass clamp that is pressed into the fuel is broken,the float needle and seat,aren't seating,or the adj needle valves are worn or not adjusted correctly,....or the float is sinking/or sticking or incorrect for this carb ....
Remove the airfilter and see if some fuel slowly pours out the carb when not running,it may flow into the engine first and then out the carb onto the deck...

Also try a different sparkplug gapped at .030"...if you have fouled the new sparkplug with an over rich micture ,it's junk and a new plug is in order...my 2 cents Jim

Well I tried the D-600 carb and same situation. I'm at a loss. I tested the compression and it read 60 psi cold after three good pulls. It seems low for a rebuilt engine but It may just be that particular engine style. I checked around but can't produce the actual service PSI. Does anyone know?

I was thinking that maybe one of the ring gaps shifted over the ports or something, although I've seen it before with little affect on compression.
I'll try a third spark plug and see what happens but I've pretty much exhausted all the energy I'd like to on this project.

Jim, this is the third carb I've tried and had the same effect, To me its a gov thing but all looks good there. I'll bet I'm missing something that is so small and stupid. I'll kick myself when I find it! And I'll find it.

Neal

Well, I have awesome spark, good fuel and air. The governor or the flyweight are not functioning properly.

Has anyone ever had this sort of problem or is it just mine?

I swear this thing is as good as when it came from the factory as far as the placement of the parts. Three carbs later, three spark plugs, three coils, two points and condensers, and two gov setups later I still can not for the life of me figure this one out.

Can someone give me some other options? I want to rid it from my bench.

Neal

Well,I believe I have found the issue ,the points need to be set a certain way ,because of the spark advance ,the flyweight may be stuck or installed incorrectly...do you have the manual to double check the gov/flyweight adjustment and the proper procedure of setting the points ????
Jim

Hey folks I have good news! I resolved the issue and I wish I would have done this about twenty five flywheel removals ago.

The stinking flyweight is malfunctioning to not allow the running leg to kick in. It must have been stuck or something Its hard to say when you cant see it in action. Luckily I have spare parts for these things. I put a different one on and off she went. So looking at the bad one it really looks identical to the other, I just don't know if it was the flyweight or the cam. I had it installed with the smaller end toward the key way and the movement was free of grease and dirt. I just don't get it. Anyway its running good and I took an old gov spring, streched it out about half an inch and I have now achieved 3000 RPM on this machine finally.
Alot of trial and error but a great learning experience.

I realize most people don't care too much about these old point ignition engines but they sure are fun to restore and work on.
Thanks again, Walt ,Jim in VT, and Mike for the help, I know we would have found something Jim, you were on the right path.

Thanks, Neal in Kansas