The Right Jet??

Backwoods1989

New Member
Nov 10, 2021
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So I've been attempting to get this running right. This is a 58 jet on a 66cc engine. It looks way rich. However I feel that lower than 55 is just too lean, or should be.
 

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Backwoods1989

New Member
Nov 10, 2021
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I've brought the squish clearance down to 0.030 maybe less. Its giving me a cleaner burn for sure. You can tell which side of the head is intake and exhaust. Theres enough turbulence and tight enough clearance that theres hardly any burn on the piston where the squish band is, its almost clean. This is on a 58 jet mind you. Still looks really rich for some reason. Has no sign of being lean. On the piston it's clear most of the burn takes place right where its supposed to. In the chamber.
 

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Backwoods1989

New Member
Nov 10, 2021
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Amsoil saber at 95:1. I had tried others and was getting a similar result at 32:1. Maybe this engine just runs this way. I'm hesitant to keep going down from a 58 to a 55. I don't think I have read of anyone else running a small jet like this. Theres no issues with the 58, it just looks richer than it should be. I'm considering switching to ethanol actually. I have 2 gallons ready. I plan to take a small sample and mix a small amount of oil in it, just to make sure it mixes right. From what I understand amsoil synthetic will mix with it. I'm going to find out. I'm really not worried about any of the common issues with it. It's not beyond my means to repair it and it isn't my main transportation. I'd just be interested in whether or not it runs better. I plan on starting at the 72 jet, if my motor is running rich with a 58, hopefully I can get it spot on with a 72 or 74 with ethanol. I like it personally. I think it burns cleaner and runs cooler.
 

Larry Trotter

Active Member
Nov 26, 2017
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Larry after reading his other threads it looks like he is using E85 fuel, if the engine lasts this may be useful information.
Well if he is running a 100 to 1 mix I doubt he will have much time to experiment with it. He doesn’t say what problem he is having however.
 

Larry Trotter

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Nov 26, 2017
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Also E85 requires a much richer fuel/air mixture than normal gas so I don’t understand why he is going to smaller jets.
 

curtisfox

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Dec 29, 2008
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I believe he is just in the proses of trying E85 and said he would have to go to bigger jets. I sure wish they would post in one spot instead of all over the forum, it get really confusing .........Curt
 
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Larry Trotter

Active Member
Nov 26, 2017
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Last that I saw he was running a 55 and was wondering about going smaller. Guess I am missing something.