1976 Lo-boy 185 no power

[Spike83]

Hello,
I am a new guy here and wanted to say "Hello". I have been wanting a Cub Lo-Boy since I was a kid and finally the stars aligned and I bought a 1976 185.It is in nice shape, has some issues. Leaking rear seal, clutch throw out bearing shot. Previous owner put in new plugs, distributor cap, rotor but not points. He is sending those to me. It has a Zenith carb which I cleaned yesterday, took all jets out, ultrasonic everything. The issue is that it seems to me to be running rich and it stumbles on acceleration and completely falls on it's face when putting any type of load on it, especially the mower deck. Idles just fine, starts up like it was new. I'm a Cub Cadet guy so I am stumped as to where to go next with it. Grass is growing and I'm in need of your combined expertise. Thanks for having me, I appreciate all input.


Randy

[Don McCombs]

I would first perform a compression check on the engine, dry and wet. Report back with the results.

[Spike83]

Hello Don,
Thank you for the reply. Just finished a compression check...all plugs out, full throttle,choke pushed in. Cylinder 1=130. Cylinder 2=120, Cylinder 3=125
Cylinder 4=125. I didn't think I needed to do a wet test with numbers this good. The exhaust has smelled very rich since I picked it up two days ago. Cylinder 1 spark plug, black, lot of carbon in it. Spark plugs 2 and 3 seems a little wet but not black and cylinder 4's electrode was clean almost golden in color. They are new plugs PO put in. Checked gap, all at .023. Going to go look at the points next since it is something that has not been changed.
Any more suggestions are clearly welcomed and needed.

Randy

[Don McCombs]

If the valves have not been adjusted recently, and I assume they haven't, that would be a good next thing to try. No expense except your time.

[Spike83]

The manual states that the manifold has to come off to do that job, looks like if you took the carb down it would be quite a bit of room. Have you done it without removing it? Thanks

[Don McCombs]

Easier if the manifold is off, but not absolutely necessary.

[Dale Finch]

I just did mine today...lowered the carb...left the rods and air cleaner hose attached but did disconnect the forward end of the gov/carb rod (easy to get to!). Was able to lower the valve cover and get in there just fine. After I had finished, I even slid the cover forward and removed it to clean it and check the gasket.

BTW, the last time I adjusted the valves on this cub, I used Indian Head Varnish, but on the cover side only. I am so glad I did. Even if it gets "wet", by not having the sealant on both sides, it made it easy to remove, and more importantly, it kept the gasket in place while installing the cover.

Oops! Just realized this was about a 185...so not sure if this holds for that model...sorry!

[SONNY]

Sounds like the inlet needle is not holding gas back or float is set too high. --- you might check that part if you get a chance. ---Don't take much to throw these motors out of whack. ---At least on mine that's the case!

[Spike83]

Ok. Valves adjusted. Slight changes on a couple of them but not really that much. Everything looked very clean in there. No broken springs. Everything set at .015. No change in condition. When taking the carb out to get to the valves there was a puddle of gas in the intake side of the carb. I have a rebuild kit coming. When I cleaned it I noticed there wasn't a small wire spring clip with the needle valve. I didn't realize it required one till I saw what was in the rebuild kit. Anyway, there are a number of new parts coming. New clutch kit, throw out bearing, seat, belts. It's leaking oil out the rear main seal so I will be doing the swap for the remachined seal holder and seal. Can anyone tell me what mower deck I have. It has been welded on quite a bit to keep it together. I am in the market for a little better one.

[outdoors4evr]

The issue is that it seems to me to be running rich and it stumbles on acceleration and completely falls on it's face when putting any type of load on it, especially the mower deck.

Welcome Randy, You may have a couple of things going on here. The plugs do indicate it running a bit rich. Hopefully this is solved by adjusting the float. Here is a picture to help set the float.

ZenithFloatSettings.jpg (10.94 KiB) Viewed 912 times

Regarding the stumbling, this is usually attributed to the idle air adjustment on the carburetor. This is the adjustment on the top of the carb toward the back of the intake tube. This adjustment allows more or less air into the carb at lower throttle setting. Backing the screw out lets more air into the carb which makes the mixture more lean. Threading it in lets less air into the carb which makes the mixture more rich. This adjustment is pretty finicky. Start by making 1/4 turn adjustments and then dial it in with 1/8 or 1/16 turn adjustments.
Mine runs best on the edge of lean while at an idle. The transition from idle to wide open should not stumble. Do this transition often while adjusting first without a load. Then try it with a load to fine tune. (take the left blade off the mower deck for safety)

[gitractorman]

Sounds to me like it's only running on 3 cylinders. Nobody's mentioned it yet, but I'll bet anything that this is the problem. I've had more than 1 Cub or Lo Boy that started up and ran great, but had no power, and turned out to only be running on 3 cylinders. You can check by starting the engine then pulling the plug wires with a pair of pliers or channel locks, (with rubber handles!) I'll bet you'll find one that makes absolutely no difference in the engine running when you pull the wire, and that's the cylinder that is not firing. Mine always turned out to be bad plugs, even when it was new plug, but could be the wires too, especially if they installed wires that you have to cut and fit the boot on. It's real easy to not get the connections right with those wire sets.

[SONNY]

Cant tell about the mower,---does it have 3 drive belts or just one? If 3 its a danco and if one a woods 59.

[Spike83]

Hey Sonny, it has 3 belts.

[SONNY]

o.k. that would make it a Danco. I have a couple of them out here in the junk. ---one is still under an Allis C tractor. I dont use them anymore. They did work ok but I went to a woods 59 on my 185 and moved up to a couple big sunstars for serious mowing!

[SONNY]

I have a decent looking Danco deck here if you want to come get it. Cant' beat free!--- It's not welded up or ate out. Its complete and on one of my Allis C tractors and when it comes off,--it goes in the junk. --- I will never use it. also have a couple old woods 59's for parts, or use that needs a new home.