Hutzl 029 conversion to big bore questions/comments

[dsw41175]

OK, I know the quality of these may be of question but with the 029 only with 100 psi had to do something. Ordered the kit and finally got it (slow). Now for some comments/questions for those who may have done this or want to:

1) The lit mostly fits the 029 shell. The biggest problem is that the motor mount with the bar stud is not threaded deep enough and now the other bar stud and sprocket do not line up. Notified them and I guess we shall see what they say. This is a show stopper.

2) The replacement has a decompression valve while the OEM did not. What to do? I believe they included a plug also so should I swap this?

3) the kit included a spark plug that has a permanent cap on it and is not compatible with the 029 plug. I'm wondering if this is an omen.

4) Pulling on the motor seems to have good compression. However, will not fire. Good spark and the air cleaner is good. Poured some premix into the carb and still no fire. I did put on a new muffler so may put on one of the less restrictive old ones as an experiment. Safe to run with no muffler? Anything I may be missing or should test?

Need to pull the old 029 motor apart too and see what it looks like. Worst case may be getting some OEM parts.

Any input is great and I'll keep you posted.

Thanks!!

 

[HarleyT]

Recheck the flywheel key.

 

[earlthegoat2]

Do a compression test. Many of the less expensive aftermarket cylinder kits have high squish.

Get a spark tester and check for spark.

 

[fearofpavement]

So you're talking about the whole engine and not a replacement cylinder/piston kit?

 

[dsw41175]

Appreciate all of the comments and did some more looking today. Checked the flywheel and it is indexed and gapped correctly so should be generating spark. I need to get a spark tester to confirm. The compression is a big worry now. Just under 50 psi with the throttle wide open. I've sent them a p;picture of the bar stud not aligning with the other parts and I guess I need to see what they say. I hope they make good on this. While I was out I took some picture of the original motor. Any comments? There is some scoring but I wonder if new rings would fix the compression.

 

[jakethesnake]

How are you checking the compression? To be honest I’m not exactly sure what you’ve done. You put a whole new crank inside?

 

[Poleman]

Did you purchase the whole Hutzl engine kit?? You can use the pan from the other engine and things should line up. Make sure the crank seals are straight and not cocked. What sealant did you use to seal this up with? Use the plug to close off the decomp.
You can check for spark by taking out the plug and using a screwdriver to ground it while pulling it over. Or you could have a friend hold the plug while you pull it over....you’ll get instant results with that method if you have spark.

 

[dsw41175]

Great feedback and appreciated. Compression was checked with the throttle held wide open and pulling a number of times and then repeating. Was very consistent (low). This was supposed to be the drop in engine (entire) which comes unsealed. I thought that this would be the easiest route. I used Yamabond 4 for the seals and the base/head interface. As I have to take the entire saw apart again (easier the second time) I'll use the original base with the new top end and replace the decompression vale with the supplied plug. I'll also do a complete spark check once reassembled. Has anyone ever had these parts fail when swapping the motor? Just curios. I'll keep you all posted. Thanks!!

 

[jakethesnake]

You saying that brand new piston is scored without ever even getting it to start?

 

[dsw41175]

Sorry if I confused things. The picture are the original (21 year old) Stihl parts. The "new" motor is the one that will not start. Given teh issues with the "new"motor I was pondering just putting new rings in the original motor to see if I had good compression.

 

[jakethesnake]

Got a different saw to put your tester on? Sometimes they can act strange. Just to confirm tester is correct. Do you have spark if you ground the plug outside the cylinder?

 

[Poleman]

That sure is an option, putting the old engine back together. It doesn' look bad other than some wear on the skirts of the piston.
Take out the old rings slightly smooth any rough spots on the piston witH 400 sandpaper and oil, don' go overboard. Then do the same with the cylinder. Clean both up meticulously, put in new rings, liberally coat piston and cylinder and assemble. This should give you good results.
Only issue to address is the spark issue as that' not a p/c problem. Make certain all wires are where they should be, coil, cylinder post, on/off switch.

 

[dsw41175]

I will likely have to go this route as the seller has gone quiet. Anyone have a preferred ring brand?

 

[jakethesnake]

Caber

 

[fearofpavement]

I would just use the Huztl piston and rings. Put them side by side to make sure they're the right size. You sure you didn't get a 46mm piston with your 49mm kit? Not sure how the compression could be that low. That's really really low. Like you forgot to put the piston rings in, lol.
As stated, confirm your compression checker with a different piece of equipment.
although others claim differently, I've never had different readings between throttle open and closed when doing compression as the exhaust is open when the intake is sealed.
If the compression is as low as you say, that's why it won't start. So begin with confirming that before suspecting spark issues.

 

[fearofpavement]

When checking spark on this model saw, I use an a wire with an alligator clip on the engine fin and a battery charger clamp around the metal of the spark plug. It requires a jumper wire to get ground as you can't just lay the plug up against metal since there isn't any in the vicinity.

Did you pull the compression valve closed before checking compression? Even if it was open, it should read higher than what you got.

 

[dsw41175]

I was just going to write back about checking the spark and that is exactly what I did. Took and alligator clip (one on each side of a wire) and went from plug ground to the shut off ground. Blue spark so that is good. The vendor did finally get back and wanted me to disassemble and reassemble to see what happens. Took it all apart again yesterday and cleaned everything up. Took the decomp vale off and plugged the hole. Got dark on me so back to it today. Any pointers for getting the piston rings (easily) into the bore? I'm thinking the tin can and hose clamp method but open to suggestions. I have to admit I am getting much faster at taking the saw apart through all of this. Not sure if this is a god thing or not ...

Thanks all.

 

[Khntr85]

Did you seal the engine together yourself....


Did you check gap on coil...



You got a 390 kit, no 290 has a compression valve.....you will want to plug it...AM decomp valves are absolutely worthless, never trust one!!

 

[Leerod83]

As far as the rings go, I usually just lube them with 2 stroke oil along with the piston and some wiped in the cylinder. Then just kind of work them into the cylinder. It's somewhat tapered on those models so a ring compressor isn't a must have. If you're careful and make sure the ring gap is where it's supposed to be you shouldn't have too much issue just working the piston assembly into the cylinder. And yes these saws they get easier every time.