Husqvarna 394 won’t stay running/barely starts

[huskyboy]

Where would I go to order all that for $35?

The piston itself is about 35-40$ depending on who you get it from

 

[TBE]

Ok so after I rethreaded the spark plug whole, compression seem to hold at 7 psi with very, very slow decreasing.

Figured while I have it apart though...I’d take a little ok at the cylinder, piston and rings and replace if necessary. What do y’all think?

 

[Ozhoo]

If you're gonna use that cylinder, I wouldn't put any more money into it... Unless I'm seeing things that aren't there.

 

[Ketchup]

The cylinder looks like it has some transfer. The piston looks to be at the end of its functional life. I've seen people reassemble something like this with new rings. They run, but compression and power never return to a high level. If it were mine I would sand the transfer out of the cylinder and put in a new piston and rings. I would also replace the fuel line, crank seals and rebuild the carb.

Check your bearings if you do the seals.

 

[TBE]

Ok so after I rethreaded the spark plug whole, compression seem to hold at 7 psi with very, very slow decreasing.

Figured while I have it apart though...I’d take a little ok at the cylinder, piston and rings and replace if necessary. What do y’all think?

The cylinder looks like it has some transfer. The piston looks to be at the end of its functional life. I've seen people reassemble something like this with new rings. They run, but compression and power never return to a high level. If it were mine I would sand the transfer out of the cylinder and put in a new piston and rings. I would also replace the fuel line, crank seals and rebuild the carb.

Check your bearings if you do the seals.

Thanks! Fuel line has been replaced and carb is rebuilt. When you say “sand the transfer out of the cylinder”...what do you mean? Could elaborate on it?

I’ve rebuilt my JD 212’s Kohler engine last winter and had to deglaze the cylinder but I was told not to use sandpaper so I bought a Flex Hone cylinder home and it worked like a charm!

I’ll get new seals, piston and rings- and head gasketof course.

If someone could tell me the proper way of reconditioning the cylinder, I’d greatly appreciate it! Thanks!

 

[huskyboy]

Ok so after I rethreaded the spark plug whole, compression seem to hold at 7 psi with very, very slow decreasing.

Figured while I have it apart though...I’d take a little ok at the cylinder, piston and rings and replace if necessary. What do y’all think?



Thanks! Fuel line has been replaced and carb is rebuilt. When you say “sand the transfer out of the cylinder”...what do you mean? Could elaborate on it?

I’ve rebuilt my JD 212’s Kohler engine last winter and had to deglaze the cylinder but I was told not to use sandpaper so I bought a Flex Hone cylinder home and it worked like a charm!

I’ll get new seals, piston and rings- and head gasketof course.

If someone could tell me the proper way of reconditioning the cylinder, I’d greatly appreciate it! Thanks!

Try some 220 or 320 grit sandpaper first and see how it goes

 

[TBE]

Try some 220 or 320 grit sandpaper first and see how it goes

What am I looking for though? Crosshatch like in a bigger engine? What do I want it to look like?

 

[rupedoggy]

Is it possible for you to do anything without help? Do you know how to use the search function?

 

[TBE]

If you're gonna use that cylinder, I wouldn't put any more money into it...View attachment 663309 Unless I'm seeing things that aren't there.

What is it that you’re seeing? Just the transfer?

 

[TBE]

Is it possible for you to do anything without help? Do you know how to use the search function?

Haha thanks for contributing. No need to get sassy though...

I’m sure you weren’t born knowing everything either and at one point or another were in the position where you needed guidance because you didn’t want to mess up your expensive machinery.

If I am mistaken though and you were born with a wealth of knowledge, my apologies. I’ll get to googling.

 

[Ozhoo]

What is it that you’re seeing? Just the transfer?

Is the plating worn/flaked off? If not, then clean up that transfer a little better and you're good.

 

[TBE]

Is the plating worn/flaked off? If not, then clean up that transfer a little better and you're good.

View attachment 663394

Gotcha, thanks! You guys have been extremely helpful and I truly appreciate it!

 

[HarleyT]

Is the plating worn/flaked off? If not, then clean up that transfer a little better and you're good.

View attachment 663394

Looks like potato chip flakes....

 

[TBE]

Looks like potato chip flakes....

Haha maybe...?...

Nah.....guess I coulda done a better job of cleaning it before th photos. I found a link for cleaning the transfer off so I’ll post photos when I’m done and hopefully it gets a “passed” inspection from y’all. I ordered a meteor piston and that’ll be here on Thursday so hopefully o should have everything back together by this weekend and I can start working on the backlog of customers.

 

[rupedoggy]

I was not born with knowledge. I did however acquire common sense. In 1986 I bought 6 boxes of 125 Mc parts saws. I knew nothing of chainsaws. After putting 4 running saw together, without the internet or any friends that could help, I learned. You have the greatest help around but sheeze help yourself a little anyway.
A good example of not using your noggin is asking if cross hatching is desirable. A new cylinder is as smooth as they can make it. It is ready to install. There is no break in for two strokes (well a little). Only people that work on four strokes think honing and cross hatch (and maybe some Chinese). LEARN. Mike

 

[TBE]

I was not born with knowledge. I did however acquire common sense. In 1986 I bought 6 boxes of 125 Mc parts saws. I knew nothing of chainsaws. After putting 4 running saw together, without the internet or any friends that could help, I learned. You have the greatest help around but sheeze help yourself a little anyway.
A good example of not using your noggin is asking if cross hatching is desirable. A new cylinder is as smooth as they can make it. It is ready to install. There is no break in for two strokes (well a little). Only people that work on four strokes think honing and cross hatch (and maybe some Chinese). LEARN. Mike

Great, thanks for answering my question! I am LEARNing.

 

[rupedoggy]

Okey dokey

 

[TBE]

So I cleaned it up- I think- and I’m afraid Ozhoo might be right about the worn plate...especially under the exhaust port. What do y’all think? Is it worth putting a new piston in?

 

[Ketchup]

Not sure. Is that dirt on the cylinder wall or little chipped out spots? Chips wouldn't be good.
It might just be the light, but the sanding looks a little coarse. I do 180, then 280, then 400, then scotchbrite pad. It doesn't look like you have sanded too much at the port edges, but be careful there.

 

[TBE]

I’ll sand again and try the scotchbrite pad too. And yes, I think those are chipped out spots...I cleaned out the whole cylinder after sanding. Is it a goner if those are chips?...