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Engine question


fxcarden's Avatar
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Join Date: Feb 2005
Posts: 423
NJ

04-18-06, 08:23 AM   #1  
Engine question

I have a Craftsman Chipper / Shredder / Vac unit with a Tecumseh 4.5 HP engine. This was left behind by the previous owner, and I have no idea how old it is, but it doesn't seem like it is very old....certainly no more than 5 years old.

Anyway.....I've always had some trouble starting it when cold, but I've managed to get it started by removing the air filter, and using starter fluid as I pull the cord......granted, it isn't the best way to go, but it does work.....once the engine is warm, or in very warm weather, it starts by itself without having to do anything......

The other day I was using it, and all of a sudden it spewed out blue smoke for like a minute, and then it continued to run without any smoke.....after a few minutes it started to misfire, but by then I was done with my work......

Yesterday, I tried to start it, and it won't start at all....I removed the plug, cleaned it, and still no dice....I bought a new plug which I will try tonight, but I don't have much hope.....


Questions:

Is this thing worth reparing, and how much should I expect to spend ( I live in Northern NJ ).

Could the blue smoke signal the death of the engine ?.

Someone mentioned the coil may have gone bad. Is this expensive to replace, and is it a do it yourself deal, or do I need some expert to do it ?. I suck at engine work.


Thanks !

 
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v8driver's Avatar
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04-18-06, 11:25 AM   #2  
The things to check are spark (tester is better but grounding to engine and pulling it over will do) and checking compression. Sounds like its getting fuel even though its not good....(carb rebuild would probablly help it alot)

 
ChrisHarris's Avatar
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04-18-06, 12:03 PM   #3  
Blue smoke is oil.

Burning oil is a bad sign. Sounds to me like one or both rings is letting oil slip by and it's getting into the combustion chamber where it's being burned and making the blue smoke.

This is not a good sign.

If it was me, I'd do a compression test on it. Thats a quick way to determine if your rings are damaged or starting to fail. You should be seeing at least 75--80 PSI on compression check. That would indicate a well worn engine. But, still useful. A compression check of 100PSI or better would indicate an engine with plenty of life left in it.

If your not much of a mechanic--then taking the cylinder off and inspecting the piston rings is probably out of the question for you.

If I was you, I wouldn't do much more than rebuild the carb and put a new plug in it. Carb rebuild isn't easy either--not for an admitted novice when it comes to engine work. The coil shouldn't be more than $20--$30--but why bother if the rings are failing and your burning oil?

I wouldn't hold out on this thing making it much longer. Sounds to me like it needs rings and a carb rebuild--at least.

 
fxcarden's Avatar
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04-18-06, 12:33 PM   #4  
Thanks. I'll try cranking the engine before putting the new plug in to see if it clears out anything (I read that somewhere), and then I'll try with the new plug. If I still have no luck, I'll have someone more qualified look at it, and then decide if I should just chuck the damn thing.

If I was to replace the machine, can someone recommend a decent one that won't break the bank (under $500).

 
fxcarden's Avatar
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04-18-06, 03:13 PM   #5  
Well....good news.......the problem turned out to be the cutoff switch that prevents the machine from running without the bag attached. The metal flange that is part of the bag coupling was bent backward, and wasn't pressing on the switch. This left the circuit open, and of course....no spark......the thing runs great now, especially after I invested a whole $2.60 on a new spark plug.

 
puey61's Avatar
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04-18-06, 03:39 PM   #6  
You still need to be concerned with the blue smoke. A faulty safety switch won't cause this. It could, however, create a slight black smoke. Are you sure the smoke was blue? If so, it could simply be overfilled with oil, if it's a vertical crankshaft engine, that is. Post back with the engine ID numbers...It will begin with 143.________.

 
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