C161 with a K341AS - Turn to start & fuse blows

[Highland Horse 0]

Hi everyone!

Recently bought my C161. It was running rough (missing, backfire) so I decided to give it a quick service and leave a major overhaul till Winter. I'm not sure it had seen much maintenance for quite a while before I took it on.

1 month later I have stripped engine; New piston rings, reground valves and generally checked it over. The engine is rebuilt and back on board. It is improved. First turnover last night and off she went. Let the engine run till warm, just on idle for 10 mins or so and then shut down. Tweaked the carb and checked the points gap after shut down. Decided to call it a day and finish covers etc today.

This morning - opened up workshop door; checked head bolt torques and oil level. Climbed on board and turned the key - 20amp fuse blew.

Changed fuse - well it might have been tired - Turned he key - same thing!

Can anyone tell me why this has started to happen. The wiring on the tractor seems to fit with the diagram in the Wheel Horse manual I downloaded.

Currently I can only point my enraged finger at the solenoid.

Apart from checking the wiring since the problem started, I have only changed the points and the condenser when I did the high level overhaul described above. I did notice that the points were set 0.045 - 0.050'

Hope the follwing info helps;

Numbers on plate containing ameter; 0116KH81 24308 and below 2284

Engine is a K341AS

Spec - 71311

Serial no - 120480027 (1982)

Look forward to hearing from you and getting my Horse running well in the Highlands of Scotland.

Thanks,

Bruce

[Sparky-(Admin) 19,756]

Since it was fine before I tend to think your wiring is probably correct but....I bet there is a pinched or shorted wire somewhere.

Time to hand trace the exposed wiring. Start at the fuse and work it in both directions.

And of course>>>> !

Mike...........

[Save Old Iron 1,564]

Bruce,

I would be happy to help. Failing a quick visual inspection of the wiring, let me know if you have a multimeter to measure resistance. Instead of guessing which part of the wiring may be bad and blowing several more fuses, we can unhook the battery (+) cable from the battery and hookup the ohmmeter to the battery (+) cable.

The resistance to ground would need to be less than 1/2 an ohm to blow a 20 amp fuse. We can start disconnecting wires (points wiring, wiring to ignition coil, starter solenoid, etc) until the ohmmeter jumps up to a more suitable resistance. Once the meter jumps off a 0 ohms reading when the sort is removed, we have found our problem area.

Let me know what electrical troubleshooting tools you have to work with and we can devise a plan.

As frustrating as this is right now, what appears to be a consistent dead short to ground should be quite easy to locate.

[Highland Horse 0]

Hi Sparky & Save Old Iron,

Thanks for the welcome. I'm delighted to be the owner of a Wheel Horse and hope to get mine back to it's full glory. I used to do quite a bit of work on old cars and the like, I'm quite pleased I held on to my tools! If I have a weak point it's with electrics!

Since I registered here and left my post I did examine the wiring and cannot find any pinches or short on the 'open' wires (i.e. those not wrapped up with others in tape). I had the seat off, the rear area stripped down, primarily to remove and flush out the fuel tank - it was full of all sorts! This gave me a good opportunity to check the wiring through to the seat safety switch, and through the area where the steering column comes down etc. I have not undone the wires that have been taped up, I'm tempted but I reckon that it should be ok since this problem just started and they are not near any moving/chaffing points. I know what you're thinking!... Do it anyway!

The line the fuse is on runs from the key switch to the solenoid, mainly pretty straight and open but it does join half a dozen others in a taped section.

I do have an multi-meter and will be really glad for your advice on how to hook the ohm meter up to test the wiring.

There has also been a bit of a development (British understatement!)

Now, you must understand, I am desperate to get my grass cut so excuse the over-enthusiasm/eagerness! I started the engine by bypassing the solenoid using a piece of cable (Start key in the run position). The engine fired up and was running very nicely.

So I hooked on my mowing deck and started to cut the grass. I have a fair area to cover. Things were going really well; I kept the tractor in a low gear and was making good progress through reasonably light if longish grass (4-6" max.) - at no point did the engine or deck sound as if it was working too hard. My garden has a number of sloping areas too.

After about an hour the engine tone changed and within seconds blue smoke started to come from the breather hole. I shut her down imediately! The engine was very hot. I pushed the tractor back to the workshop, left it sitting at the door to cool and went and made a cup of tea.

Later that evening I tried to turn the fly wheel by hand and it moved quite freely. So, at least I haven't cooked the engine solid.

Any ideas why this has happened? Could I have done something wrong when re-assembling the engine (only had the piston, rod and valves out). Obviously I will have to open the crank case again and check things out.

I look forward to hearing from you and again thanks for your help.

Bruce

[Save Old Iron 1,564]

Your overheating ?? issues are the primary concern now. Recheck your valve clearances and points setting. The 0.50 points gap you mentioned earlier may be a factor again. Perform a static timing procedure with the multimeter (I'll lookup the link to the procedure and post later tonight). Check your carb settings for high speed operation being too lean. Did you confirm proper piston ring gap? Proper rod / crank gap with Plastigauge? You may also need to inspect the internal parts of the engine for possible damage.

The fact you spent time cutting grass confirms most of your wiring is correct. The problem may be in the start circuit solenoid as you suspect. A quick resistance measurement of the solenoid trigger terminal to ground should show around a 5 to 10 ohm value.

Is it possible you ran down the battery to a point where the ignition spark became weak and the engine died?

[Save Old Iron 1,564]

Later that evening I tried to turn the fly wheel by hand and it moved quite freely. So, at least I haven't cooked the engine solid.

You also mentioned valve work. If the engine turns over by hand much easier than you would expect (or cranks faster than you would expect), you may be loosing compression from a stuck valve. If you let the tractor cool off and then have greater compression when turning the flywheel by hand, suspect a valve hanging up when the engine gets hot.

[Highland Horse 0]

_{Thanks for coming back to me with your suggestions and thoughts, greatly appreciated! I will look at the wiring round the solenoid when I get over the current problem. The battery is in really good shape. Is the trigger terminal the one with the +ve from the battery or the next one round?}

_{Anyway the cause of the overheat...}

_{I stripped the engine back down last night to find that the rod cap bolts were loose (well, one particularly). On closer inspection it had stripped the threads in the rod, in just one bolt hole - I could peel the stripped metal from the bolt threads. I guess one of two things; I torqued them to hard - swear I didn't, remember taking care on the re-assembly process, and I'm now questioning the accuracy of my wrench. Or the cap/rod/piston assembly should have been replaced when I did the first service, was tempted at the time but it seemed to be in good order so I re-installed it.}

_{Anyway I'd be really grateful for your thoughts; The rod & cap (and piston etc) will need replacing now. The failure has caused the faces of the cap and rod to be stripped and the surface of the crank shaft where it connects has a number of lovely grooves and generally feels rough as a gravel track. I guess the only option is to find a replacement crankshaft along with the other parts I'll need? Or can it be re-done? I've found a good engineering firm in Inverness.}

_{On the positive the valves, and other parts are in good shape, no sticking etc. I'll need to strip out the whole case and clean out the mess - When I drained the oil I did it through a screen to catch any metal/deposits to help me understand the seriousness of the problem. No metal bits came through but the material that has been stripped off the rod and cap facings has given the oil a 'sheen'. It doesn't feel gritty at all but I'm concerned that the particles mixed in with the oil might have a wearing effect. What do you think?}

_{Thanks again, look forward to hearing from you.}

_Bruce

[Highland Horse 0]

PS I'll take some photos and post them. It'll make a good record. Also; do you know any good sources for parts that would supply to Scotland? So far they seem expensive here - I getting used to the term 'Kohler parts are dear!' from people I've spoken to in the UK so far.

[Save Old Iron 1,564]

Bruce,

you are correct. Kohler branded parts do demand a premium price over non original replacement parts. My advice is to jump over into the "Euro" section of the forum and get the best feedback as to where spare parts are priced the best for import into your area of the world.

The sheen you see in the oil is finely pulverized aluminum / alloys suspended in the oil. Yes, this is destructive if left too long in a running engine. I assume you will be changing the oil when you repair the engine.

The crankshaft is likley repairable. The crankshaft journal can be machined down to 0.010 inches under the original size and a "10 under" rod can be purchased for replacment onto the newly machined crankshaft. I have never personally tried it, but there is a method of dripping muriatic acid on the crank journal to eat away the aluminum deposits without harming the crankshaft surfaces. Of course this would only be worth the effort if you knew the dimensions of the crank journal would not require machining in the first place.

Depending on your experience with the possibilities in machine work, and measuring and inspecting the parts that require machine work, the best advice may be to take the block to a machine shop. The crank will need work, rod replaced, piston skirt and ring groves inspected, and block bore inspected. You may also end up with buying a "10 over" piston and having the block bored to remove any irregularities in the bore.

Also, don't limit your repsonses to this problem by leaving this post in the electrical section. You may wish to start a parallel post in the ENGINES section. Sometimes readers stay in a certain section of the forum and not frequent other sections that are outside their comfort area or interest. Best to get your problem under the noses of as many good engine experts as possible.

[Wheel-N-It 2,967]

The fact you spent time cutting grass confirms most of your wiring is correct. The problem may be in the start circuit solenoid as you suspect. A quick resistance measurement of the solenoid trigger terminal to ground should show around a 5 to 10 ohm value.

Is it possible you ran down the battery to a point where the ignition spark became weak and the engine died?

Agreed!

Also, I now have a K-341 AQS in the machine shop for a full rebuild. It will cost me $700 US Dollars for all the machine and rebuilding work. Plus another $100 or so for the rebuilding the carb with new throttle shaft bushings & etc. Hopefully that will help give you an idea what to expect where you live.

Van

[JackC 616]

<<I guess one of two things; I torqued them to hard - swear I didn't, remember taking care on the re-assembly process, and I'm now questioning the accuracy of my wrench.>>

Depending on the type of torque wrench they can get way off. Perhaps the simple inexpensive beam type with long pointer is the safest kind compared to those with more complicated mechanism that can become out of spec. and need to be calibrated frequently.

[Save Old Iron 1,564]

Bruce,

this is the trigger terminal of a typical starter relay. An ohmmeter should register between 5 to 10 ohms when the meter is connected between the trigger terminal and ground.

[Highland Horse 0]

Hi there,

Thanks for the tips on the solenoid Save Old Iron, I'll give it a go. It crossed my mind that this conversation was going on in the Elecrical dept when I logged out last time. I'll certainly take it into the more relevant section. And I've said hi to my European friends - see if they can help with sourcing parts.

Thanks Wheel-n-it and JackC for your support too.

Situation so far is I will finish stripping the engine down tonight and get it in to the engineers tomorrow. It certainly needs a re-bore as well as the big end reduced. And get parts to match.

I'll keep the postings coming, with some photos, for those interested as I re-build.

Cheers all,

Bruce

[Wheel-N-It 2,967]

Looking forward to your updates Bruce.

I hope to have my K-341 back from the engine rebuilders in the next week or two.

Van