[jolanda]

My JD 100 still has the original Briggs & Stratton 8hp engine.
The type/code is: 190707 5147-01

The tractor worked well but suddenly after a 1h ride I was not able to start the engine again. I checked and serviced every “usual suspect”. Cleaning the carb in an ultrasonic cleaner (very cool thing !), renewing of the ignition plug and installation of a contact free transistor based ignition system wasn't leading to success. I also tried a brand new carb.
I finally opened the cylinder head and was shocked. Small metal parts on the piston and cylinder head. Many deep scratches on the cylinder wall.

Today, one week later the piston, rod and cylinder block are disassembled. Small metal parts were also in the oil.
A “020” is engraved on the piston head. Is that kind of mark for the oversize 0.020” oversize piston? It seems to me that one of the pre owner drilled out the cylinder already and installed the oversize piston.

I spoke with a shop specialized in oldtimer restaurations. They explained me an interesting procedure to fix my problem: 1.) Drill the cylinder to over-over-oversize 2.) an iron bushing will be pressed in this cylinder block 3.) this bushing will be drilled to b&s standard piston size 4.) new b&s standard size piston and rod will be installed

Sounds great but its expensive… :-( And other parts are probably worn out due to metal parts in the oil and need to be replaced too.

Another alternative would be a “new” engine. Its nearly impossible to find a used B&S 190707 5147 in germany but what about other engines? I know the stepped shaft (1” to ⅞”) is very special but its possible to convert the original JD 100 pto clutch to the standard 1” shaft. I found some howtos already. My JD 100 is used for pulling things only - no mowing so far. So I can run it without the original pto clutch.

What is your recommendation for a new engine for the JD 100 ? I dont want to change anything on the hood or frame and I like to use the original fuel tank.


Best from germany,
Jolanda

 

[tommyhawk]

You are correct thinking the piston marking means 0.020" oversize. Have you inquired at a Briggs dealer to see if any of the internal parts are still available?
Looking for a used engine in good enough condition to rebuild is one possibility. Finding one that has the proper stepped crankshaft is very difficult even here in the U.S.A.
The blue colored one I posted in the other thread came out of either a Craftsman or Dynamark (1970's era) mower. It was just like the 100 engine. It was good enough to rebuild for the 100. That was nine years ago and parts were still available. Sorry I don't know which machine it came from or whether either of those brands were ever sold in Germany.
IF you can find a good 8HP Briggs engine with a long enough crank shaft (PTO end) the step could be machined and the keyway recut. Some here have had the PTO clutch bore machined and the keyway recut to fit a straight crank.
The small engine compartment and the unusual gas tank mounting on the 100 doesn't allow an easy solution without alterations.

tommyhawk

 

[jolanda]

Yes - yes - yes ! I found an old Murray with a Briggs & Stratton 8hp engine for a good price. Its a 1975 model and a 19000 series engine like the original in my JD 100.

Original: 190707
from the Murray: 195707

The engine seems to be in a very good condition and I placed it already in my JD. Everything fits perfect except the pto clutch. For sure the new engine doesn't have a stepped crankshaft. Its a regular 1" shaft.

But I found a shop with drilling machines next town. They offered me to drill out / expand the pto pulley from 7/8" to 1".

I was surprised by realizing that the bold in the crankshaft fixing the pulley from the pto is bigger compared to the original stepped shaft. The owner of the shop never saw a B&S crankshaft with that kind of bolds. But he recommended another B&S workshop being in the business for 50 years.

Quote from the shop owner: "...he is the goto guy for those kind of cases. He has a magic black box storing all bolds from old un-repairable B&S engines. Just tell him Karsten sent you. He will help you out !"

I drove to this guru immediately and I must say he is awesome. ;-) He saw both bolds. The old and quite long and the new very short one having a bigger diameter. His take on that was just: "Hey young friend you picked a very rare version of the B&S 195707 ! But I can help you."
He opened his magic black box and picked the perfect matching bold !!

Long story short; Its really a great fun to restore this JD 100 and meet so friendly and open people helping me out. ;-)


Best from Germany,
Jolanda

 

[tommyhawk]

Very good news, Jolanda! I'm not familiar with the term "bold". Does that describe the output end of the crankshaft that I referred to as the PTO (power take off) end? Your English is perfect compared to mine, but I know phases, abbreviations, or descriptive words are confusing in translations.

Since you are into the John Deere lawn and garden hobby, I have some questions for you. In the U.S., JD started marketing the small 110 garden tractor in 1963. When were JD lawn and garden tractors first available in Germany? Are any built in plants there? If so, when did manufacturing start there?

JD has built farm tractors and farm equipment in many countries for years now, but I had not thought about the lawn and garden size until now. It would be nice if you can share some JD history with WFM members that you find interesting.

tommyhawk

 

[jolanda]

That´s what I meant... I am not a native speaker. ;-) Sorry for the typo. I was writing about the "bolt = screw" fixing the pulley in the crank shaft.

My JD garden tractor hobby is very new to me so I can only speak about my JD 100 built in 1975 and not about JD in general. I noticed that my tractor was manufactured in the U.S. and shipped to Germany. The original stickers explaining the pto / lever etc are in english under the german ones. ;-)

 

[jolanda]

Update about the pto pulley conversion from 7/8" to 1":

The turning shop drilled out the pto clutch pulley from 7/8" to 1" and eroded a slot.

The pto pulley fits perfect to my new 8hp B&S 1" crank shaft now. I assembled everything successfully and started to mow my garden. All worked good but suddenly after 3h I heard a rumbling sound and the tractor vibrated. I declutched the mower deck and saw the problem.....
The bolt / screw fixing the upper pulley of the clutch to the crank shaft was loosened and the threads were damaged. I was shocked because I had tightened this screw just 3h ago with max torque. I have no idea why this bolt unfixed itself except wrong washer.

Which washer are you guys using to fix the pto pulley to the crank shaft?

Best from Germany, Jolanda

 

[tommyhawk]

A quick look at JD Parts shows no washer used with the bolt. Seems strange to me. The bolt, or capscrew, is listed as JD part number 19H3315. Description is 3/8" x 24 UNF-2A x 3.00" long. Thread length is 1.00".
Is it possible the washer caused an interference with the movable part of the clutch? Or the parts diagram left out the washer?
You could try some thread locking compound or possibly find a self locking capscrew with the nylon insert that matches the appropriate length.

tommyhawk

 

[jolanda]

tom, thank you very much for the part number !
you are absolutely right - this bolt will fit in the original jd 100 engine. but i got a new briggs & stratton 8hp out of a murray tractor. i was surprised by realizing that this bolt in the crank shaft is much bigger ! the tech support from briggs and stratton told me that they had 2 different versions of the 8hp engine. some tractor manufactures asked for a 3/8" bolt and some for a 7/16"...... and my new engine from the murray tractor has this big one.

the b&s tech support gave me the exact dimensions of the thread. and i am happy that i found an internet shop being specialized in " bolts here in germany.

the correct dimension to mount the upper john deere 100 pto pulley to the 1" crank shaft of my murray version b&s engine is:

7/16" 20 UNF x 3.00 grade 8

i ordered 2 of those for 3 € ;-) hope they will be delivered beginning next week.

your idea using a self locking bolt with a nylon insert is brilliant. did not find a source to get this in germany. are those available in the u.s.?

what do you thing about loctite 243 to fix the bolt?

best jolanda

 

[akaothermick]

Jolanda, Loctite 243 medium strength thread locking compound is a very good choice, service removable with regular hand tools, it would be my choice for a application such as this,
Mick.

 

[tommyhawk]

I hadn't even thought about the possibility of a different thread in the crankshaft. Glad you knew what you had and didn't rush to get a 3/8 replacement!
The "Ny-loc" type capscrews are not something I would expect to find in a hardware store around my small town. They are considered a one time use screw. Where I used to work, some were used in the machines we built. Most fasteners were socket head type, Allen brand. Late eighties we began switching to all metric fasteners and brands changed.

I agree with the medium strength thread locker. I have installed a couple electric clutches on much newer machines that came with a new capscrew that had what appeared to be dried thread locker on it. I guessed it was activated by the heat or friction of tightening it. Worked well.

I'm still concerned about why the first screw came loose. The crankshaft rotation should help keep a RH thread tight. Before you add the Loctite, make sure the new screw engages at least one-and-one half times the diameter (.65") and does not bottom out in the crank threads with the clutch in place.

I need to search for the clutch that goes on the 70 tractor that we have disassembled in the garage. Having the similar parts in hand might help me see why a washer is or is not applicable in the assembly.

Keep us posted!

tommyhawk

 

[jolanda]

I got the new 7/16" bolts, washers and spring washers in my mailbox today. Delivery was much fast than expected.

But I think I will take some more time to analyze possible root causes of the loosened and damaged crank shaft bolt before mounting the new one. (and probably having the same problem soon...;-)

In my opinion there are to "suspects" to review:

1.) washer:
I used the old washer from the Murray B&S crankshaft. Again my new 8hp B&S engine came out of an Murray tractor built in 1995. This splint washer was used for 19 years in the Murray tractor. It was probably not the best idea to uses this in my JD 100 again..... My fault. Worn out splint washer might work in the wrong direction and could loosen a bolt. (read this in the internet during my analysis)

2.) The upper pto pulley was changed from 7/8" fitting the stepped to a 1" crank shaft. This was done by a professional workshop with precise machines. I might spend some time to check if this is fixed to the 1" in the same way like it was fixed on the 7/8" shaft.

Best Jolanda

 

[tommyhawk]

Jolanda, I didn't post this in the other thread, but in reviewing the parts for the 60 and 70 clutch, I found a washer listed with the bolt on them and a much shorter bolt. The washer didn't appear as a split (lock) washer. It is NLA. I do believe the other thread has answers as to why the bolt came loose with the altered clutch.
Hang in there! Maybe this will be solved yet.

tommyhawk

 

[jolanda]

Tom, thank you very much ! I will test the clearance of the bolt / screw head with a washer. In my opinion there should be enough space in the bushing riding the needle bearing.

 

[tommyhawk]

Yes, I think you have a good understanding of the mechanics of it. The other thread proves that. I'm very confident you will conquer this beast! I'm learning a lot from you on the conversion. Thanks!

tommyhawk

 

[jolanda]

Hi Tom, yes I have "conquered the beast" today - somehow.. ;-)

I have assembled the pto with the new bold and a spring washer after I double checked all clearances. Everything fitted and nothing loosed after driving 2h in the garden.

 

[jolanda]

UPDATE:

The upper pto pulley is still fixed by the new bolts with a regular spring washer.

(Haven´t used the Loctite so far. This is the last option in case the bolts will loose in future ;-)