Small Engines (Lawn Mowers, etc.): Engine not running right, tiny specks, exhaust ports

Question
QUESTION: Hi.
After I adjusted the new carburetor of my Poulan Pro PPB200, it seemed to idle and run just fine. When I tried to use it the next day, it wasn't idling or running right for some reason. I have it idling good again, but it won't throttle correctly.

You mentioned a crankcase leak as a possible problem, and I said I had taken it into a shop. I forgot that the guy in the shop had already suspected a dirty carb, and might not have checked for a leak, but only the compression. What do I check for to know the crankcase is leaking? If not the crankcase, what else should I check for? I noticed that a fuel line going into the primer bulb, although all the way on, is not tight. I also noticed that, although I emptied the fuel tank twice, I still see very tiny specks in the fuel.

Thanks for any help.

ANSWER: Take a look at the link below:

http://www.partstree.com/parts/?lc=poulan_weed_eater&mn=PPB2000+Gas+Blower+Type+

The crankcase o-ring, part 28, are known for leaking.  We usually remove the cover, wash with parts cleaner, and then apply Permatex #2 around the o-ring to ensure it seals.

An indication of a leak is usually associated with oily or dirty residue around the leaking seal.  I find a lot of oily residue on the bottom of the crankcase before sealing the o-ring.

Let me know if this helps.
Eric

---------- FOLLOW-UP ----------

QUESTION: Hi.
The parts diagram for my trimmer is:
http://www.partstree.com/parts/?lc=poulan_weed_eater&mn=PPB200+Gas+Trimmer&dn=02

Would I need part #19; the o-ring shroud kit?

I think the crankcase may be in the photos below, with the o-ring also in one pic (1st pic). I had the trimmer taken apart earlier because I had read similar problems caused by clogged exhaust ports. I found out the port is dirty, but not clogged, and the muffler is rusted, and has a hole in it.

Here are the pictures: http://imgur.com/a/gNOPO (Full size images can be seen by clicking a pic, and clicking the gear icon that shows up in the top, right-hand corner.)

Thanks

ANSWER: We rarely replace the o-ring shroud kit.  The Permatex #2 has always worked to seal the o-ring.

Eric

---------- FOLLOW-UP ----------

QUESTION: Hi. I put some of the Permatex on the o-ring, but the trimmer still doesn't want to throttle right.

I took the o-ring off, wiped it with a towel, replaced it and put a coat of Permatex 2 on it. I only put just enough Permatex on to cover the o-ring, but it wasn't a thick coating. BTW, the o-ring was loose fitting, and not a very tight fit.

Also, since I haven't done this type of work before (at least messing with the carb) I don't want to somehow clog a new carburetor up. Is Seafoam Motor Treatment safe for these machines. I've heard it mentioned before as a gas additive for helping to clean the carburetor.

Thanks

Answer
Seafoam is safe for 2 cycles, just follow the Seafoam directions.

Have any of the intake gaskets been replaced?  Once had a customer install a carb gasket that was too small...the intake hole was smaller than the carb hole...took me forever to find the simple problem.


Are you sure the carb is adjusted properly and is the muffler and exhaust port clear/clean?

Eric