Carb advise

[spareparts]

sorry, I have to warn you guys again about the torch tip cleaner. It will change the orfice size of any of the holes you run it thru. WE had a Yamaha engine that was runing rough under load, everything checked out when we took the carbs apart. On the dyno, its was "fourstroking" trying to hit every other time under load, indicating a rich condition. We took the carbs apart and checked the jet size against teh book,it had the correct jets. It wasn't untill we found out the owner had receently rebuilt the carbs himself did we start a closer inspection. We compared the jets in his carb against another set of the same size and discovered his welding tip "cleaner trick" had opened up the main jets by a clear margin( you could easily see the difference without any visual aid). We repalced the jets with new ones from Yamaha, and the engine ran perfect. Welding tip cleaners are made to remove metal, I use them to open up air bleeds on Q Jet carbs(allways mike the reamer to make sure its the correct size). If you can't get the jets clean with cleaner(or teh sonic cleaner), then they are usually pitted and will need replacement as teh pits will affect fuel flow. If you happen to alter the jet size on purpose, remember to polish the jet openings to remove the swirl cutting marks left by a drill or ream as it will affect fuel flow as well. We use a tooth pickcovered with lapping compound in a biderectional drill, work it just like lapping valves

[jjjtronics]

I have used the torch tip method all my life, and never ever had a problem.
The tip cleaning needles are not to be used as files, if you use them properly, they will not change the size of the jet by a measurable amount, unless you sit down and grind the hole of the jets on purpose. You can measure the needle with a micrometer, and insert the closest size for a jet, and only pass it once, just enough to clear the jet, and out.

[cterrebonne]

this is why i refuse to run carbed engines anymore.

[jjjtronics]

C-bone,
I remember when injection systems came out, on cars. BOOM !!! It was like majic, it was just too difficult for me to understand, It took me a while to swallow this technology. Today, I think it must be a LAW to install this F.I. gadget on every single thing that burns fuel.
I am waiting for my old Yami to "die", so I can get a FI one for my boat, but the SOAG don`t want to die just yet.

[cterrebonne]

Originally Posted by jjjtronics

C-bone,
I remember when injection systems came out, on cars. BOOM !!! It was like majic, it was just too difficult for me to understand, It took me a while to swallow this technology. Today, I think it must be a LAW to install this F.I. gadget on every single thing that burns fuel.
I am waiting for my old Yami to "die", so I can get a FI one for my boat, but the SOAG don`t want to die just yet.

yep thats the thing with the old carbed engines, if you take care of them they last forever. I always liked FI engines, I guess learning troubleshooting on them makes it second nature.