Rich at idle clone

[bigrob]

Hey guys having a problem with my 208cc 7hp Princess Auto clone.
I did the usual mods custom air low restriction air filter and custom exhaust header.
I drilled main jet out with a #65 bit to make it a 89-90
I drilled the idle jet with a #77 to make it a 45
This carb does not have an emulsion tube.
I have a NGK bpr6es plug installed
The engine starts fine and revs fine.

The problem is it seems to be running really rich at idle , it soots the plug up real quik and even gives a puff of black smoke when you crack the throttle open.
With a fresh plug if I start it and hold the throttle at half or full and don't let it idle ,then check the plug it is a dark tan color wich I can live with.

My question is where do I go now , do I open the idle jet up bigger ? or do I replace the main jet with a smaller one.
Rob

 

[creia]

"I drilled the idle jet with a # 77 to make it a 45."
bigrob,
I wonder if that might be the problem right there?:shrug: I know that some others on this forum advocate drilling idle jets, however, we have both of the HF 6.5 HP clones (the original "Greyhound" and the newer "Predator") and we have NEVER drilled the idle jets, and they both idle just fine, and never load up the plug.
"This carb does not have an emulsion tube."
That seems unusual/atypical to me- I thought that all these clones had one?:shrug: On both of our clones we did upgrade the emulsion tubes as well.
Michael

 

[bigrob]

Thanks creia , I thought the idle jet was just an air bleed , so my assumption was that the bigger it went the leaner it would be ?
I have a second identicle untouched engine I may switch idle jets to see if it helps going back to stock.
Thanks Rob.

 

[creia]

Sounds like a good course of action.:thumbsup: Report back and let us know what you find out, as I'm sure others can learn from this thread....
Michael

 

[TomH]

Hey guys having a problem with my 208cc 7hp Princess Auto clone.
I did the usual mods custom air low restriction air filter and custom exhaust header.
I drilled main jet out with a #65 bit to make it a 89-90
I drilled the idle jet with a #77 to make it a 45
This carb does not have an emulsion tube.
I have a NGK bpr6es plug installed
The engine starts fine and revs fine.

The problem is it seems to be running really rich at idle , it soots the plug up real quik and even gives a puff of black smoke when you crack the throttle open.
With a fresh plug if I start it and hold the throttle at half or full and don't let it idle ,then check the plug it is a dark tan color wich I can live with.

My question is where do I go now , do I open the idle jet up bigger ? or do I replace the main jet with a smaller one.
Rob

I did the same thing and got the same results. I jacked up the idle jet. That little bitty drill bit is hard to get to go thru the jet straight. My other clone I didn't drill it. Yeah, I have to choke it every time and yeah, it pops a bit on let off. But the plug looks good.

 

[creia]

"Yeah, I have to choke it every time and yeah, it pops a little on let off."
It has been my experience that these are both typical, normal and expected with the clones.
Michael

 

[bigrob]

Today I did some more testing , and the problem is solved by going back to the stock idle jet.
It still starts fine, seems to pull almost as good as before has a much steadier idle and the plug stays a nice dark grey / tan .
So now I have to get some replacement idle jets.
Thanks for the advice.
Rob.

 

[TomH]

Hey Rob, do you think a jet out of the old 2.8 might work?

 

[creia]

"... and the problem is solved by going back to the STOCK idle jet." :thumbsup::thumbsup::thumbsup:
bigrob, posting this thread (and especially sharing your solution) will help other members so that they do not drill out idle jets when not needed.:drinkup::drinkup::drinkup:
Michael

 

[bigrob]

Yes sometimes the factory knows what they are doing lol
Tom , have a couple of 2.8's and will have to check them I plan on calling a couple of engines places on monday to see if any body stocks them. It may help some of my other clones to go back to stock too.
Rob

Well I checked and the 2.8 is the same size and fits right in. Thanks Tom , I dont usualy get that lucky, maybe I should go buy a lotto ticket lol.