Head Bolts

[brett66c 0]

I want to clean the piston head on my C-125, but am afraid to because I don't have a torque wrench for reassembly. How imperative is this? Can I get by without one or is that not advised? If not, what do they need to be torqued down to?

Brett

[WH_Hobie 1]

yes you can do it with a 3/8 drive rachet and just tighten them a little over snug

Nick

[TT-(Moderator) 1,131]

The thing you need to be more concerned about is the head bolts near the exhaust port breaking off, along with twisting off the two 1/4-20 bolts that hold the top cover and side shrouds to the cylinder head.

If you are successful in removing the head, you probably won't find much carbon that needs cleaned - unless the engine is an oil-burner. Clean the mating surfaces, install the new head gasket, and torque the bolts in the correct (criss-cross) pattern to 35 to 40 ft. lb. (I usually put a tiny dab of hi-temp anti-seize on the threads.)

If you don't have a torque wrench available, draw them down about like "wh_702" (my son) suggested. Not white-knuckled tight, but enough to start to compress the gasket. You should also retorque all of the bolts after the engine has been run at operating temperature for a while and allowed to cool.

[Curmudgeon 28]

This is one time I'll disagree with TT. A torque wrench should always be used on head bolts.

[TT-(Moderator) 1,131]

I do use a torque wrench on head bolts and I always tighten them in a criss-cross pattern.

I don't condone installing a head without one (or a new head gasket) but I have reassembled a few small engines "in the field" without one and never witnessed a failure. Most of them were Briggs push mower engines though. (sometimes you gotta do what you gotta do, right?)

I was actually trying to "scare" Brett away from doing it at all unless he was experiencing a problem. I have several Kohlers that have never been apart since the day they were built (in the 60's) and see no need to decarbonize. There is enough detergent in gasoline to keep cylinder deposits under control in engines that are in good condition. (not "oil burners")

I'd just hate to see his next question be "how do I remove a broken head bolt".

I've also hear about the decarbonizing method of spraying a mist of water in the carburetor while the engine was running at full throttle. I haven't attempted it, nor will I probably try. :whistle:

[dgjks6 6]

I just cleaned the head on mine. I had to borrow a neighbors torqe wrench and followed the tightening diagram in the engine manual. I went to buy one, but the cheapest I could find was about $55.

This year I cleaned the carb - noticed a huge difference, adjusted the valves - engine stopped backfiring and ran smoother, and cleaned the head - noticed no difference.

So what is my point? Since there was no reason to do it to improve performance, wait until you can beg, borrow, or steal a torque wrench.

[brett66c 0]

ok. right now the egine runs fine, but to be honest I kinda wanted to see what was inside (even though I already know for the most apart), and if it would indeed make my engine run better. I've been doing some reading and actually got the idea from a Briggs book. So I guess this might be a good time to ask you guys "what you do for a good tune up?" (other than replace the fuel filter, air filter, oil, and a good scrubbing)

[dgjks6 6]

Mine has a kohler - so I am not sure if all of this applies, but

change oil

change air filter

change spark plug(s)

clean engine - baffles, etc

grease everything

every 500 hrs

adjust valves

clean head

lubricate starter - have not done this yet - I need to remove the dipstick to do this - so I may try at next oil change

[TT-(Moderator) 1,131]

You'll also find breaker points and a condenser on the ignition system of the C-125, along with a replaceable spark plug wire. (none of this applies to the Magnums)

Chances are, you can get away with filing and setting the point gap, but if you want to be certain these components are in perfect working order, you can replace them with new parts.

[Curmudgeon 28]

I do use a torque wrench on head bolts and I always tighten them in a criss-cross pattern.

I don't condone installing a head without one (or a new head gasket) but I have reassembled a few small engines "in the field" without one and never witnessed a failure. Most of them were Briggs push mower engines though. (sometimes you gotta do what you gotta do, right?)

I was actually trying to "scare" Brett away from doing it at all unless he was experiencing a problem. I have several Kohlers that have never been apart since the day they were built (in the 60's) and see no need to decarbonize. There is enough detergent in gasoline to keep cylinder deposits under control in engines that are in good condition. (not "oil burners")

I'd just hate to see his next question be "how do I remove a broken head bolt".

I've also hear about the decarbonizing method of spraying a mist of water in the carburetor while the engine was running at full throttle. I haven't attempted it, nor will I probably try.

Agreed TT. Don't fix what isn't broke. An experienced mechanic in the field doing what he has to do is a little different than someone doing "the first time in" in a shop. He should be using a torque wrench for he has no sense of what it should "feel" like. That was my concern.

[TT-(Moderator) 1,131]

to be honest I kinda wanted to see what was inside (even though I already know for the most part)

Thought I'd save you the aggravation, Brett. I had to pull a K-241 (10hp) Kohler apart today so it can be taken for machine work.

Now you can see what's under the head without causing an ache in yours.