Re: What's the relationship between float setting and rich/lean mix ?

Posted by John Van on September 30, 2002 at 18:22:56 from (209.170.133.171):

In Reply to: What's the relationship between float setting and rich/lean mix ? posted by Amateur Mechanic on September 30, 2002 at 15:40:54:

Typically speaking the float setting should not affect the tractors air/fuel ratio setting, however 2 problems are possible.

1. The float is set too low. In this case the float might not allow enough gas to enter the bowl to support the tractor's needs, especially at faster engine speeds/higher loads. In this case the engine would run too lean. It might skip, or tend to have weak performance under load.

2. The float is set too high. In this case it's possible that the carb bowl would overflow. Where it overflows to depends on the carb. Sometimes it simply drips out on the ground. To be sure not particularly safe. Some carbs might allow a steady trickle of fuel to be passed on to the engine. It's possible that excess fuel could also be forced into air metering jets in the carb. In these cases the air fuel ratio has too much fuel and is said to be "rich". Symptoms might be hard starting, an engine which "chuggs", black smoke from the exhaust and a heavy fuel smell in the exhaust. You might find a dark sooty deposit on the exhaust pipe. The plugs might also be quite dark and fouled.

If the float is too high and the carb trickles gas into the engine you might find that allowing the tractor to sit for several days will cause the gas tank level to drop. In this case, check your engine oil. Sometimes the excess fuel runs past the rings and into the crankcase. You might smell raw gas in the engine oil and perhaps see the oil level rise. This is especially a problem with gravity feed fuel systems (no fuel pump) which are allowed to sit without turning off the fuel.

Sometimes a carb will exhibit an over rich condition and the problem will be with the needle and seat allowing gas to seep through even though the float is set correctly. Excess wear and dirt can cause this to happen. Fortunately you can get a carb rebuild kit for most carbs that includes a new needle and seat.

Best of luck,
John

Follow Ups:

Post A Followup Name: E-Mail: Subject: Re: Re: What's the relationship between float setting and rich/lean mix ? Comments: Optional Link URL: Link Title: Optional Image URL: Email Notification: If you check this box, email will be sent to you whenever someone replies to this message. Your email address must be entered above to receive notification. This notification will be cancelled automatically after 2 weeks.

TRACTOR PARTS	TRACTOR MANUALS

We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]