Carbs revisited: Cleaning after a hot summer storage, what clogs?

[Pat Conlon]

After the 2010 WCR, last summer I was away for 5 months while my 2 FJ's sat in a hot garage (on a Battery Tender) In my '92 I put in some Stabil, but for the life of me, (stupid) I forgot to treat my '84. Yep, sure as shit, they were dry when I came home.
My bad. I know better. Time r/r to the carbs for cleaning.

Surfing through the UK FJ Club online parts catalog, I saw this statement on the Fuel Stabilizer they sell (emphasis added):
" The big problem with modern unleaded fuel is If left in the carbs after 3 months the fuel breaks down and blocks the air jet. Not the fuel jets but air jets. These are very difficult to clean due to their very small size........"

http://www.fjcatalogue.com/catalog/item/7220095/7440907.htm

Hmmm, I did not know this. Air jets? As in pilot air jets? I've always thought the emulsion tubes (aka:jet nozzles) got clogged...

[edit] fixed link

[SlowOldGuy]

Pat,
What always gives me fits is the idle jets getting clogged.  I've tried both StaBil and Marvel Mystery Oil over the last few years and neither product seems to prevent carb problems if the bikes are left to sit for anything over about 4 weeks.

My FZ1 and '93 FJ are the worst about running badly if they are not started for a few weeks.  I can dump in a bottle of Techron and that appears to clear up the problem after running through a tankful of treated fuel.  

This technique saved me on a trip a few years ago.  We left Dallas for a 5 day trip in Arkansas.  We were travelling at a pretty elevated pace the first day and I noticed that the bike was hard to start after a food or fuel break.  Once started, it idled badly, but was fine under throttle (anything above idle speed).  The first night I pulled the float bowl off the #1 cylinder (which was the only offending cylinder at idle) and did not see any trash in the bowl.  I added a bottle of Techron that night at the hotel and ran it up and down the street to mix it in and get some into the carbs.  The next morning (and for the rest of the trip) the bike was healed and ran (and started and idled) flawlessly the rest of the trip.

Of the 3 bikes, the FZ is the most susceptible I believe due to its increased number of tiny circuits and jets.

The choke orifice in the float bowl is also easily clogged by dried fuel

It's possible that the emulsion tubes are contaminated, but typically I've encountered fine sand-like debris on the exterior surface of the tube.  I've seen this mostly on engines that are using K&N airfilters.

From what I can recall, I've never had to clear a clogged air passage.  But the ethanol does seem to give the fuel the ability to climb the walls of the float bowl or up the emulsion tube.  When left sitting for a few weeks, I can remove the diaphragm slide and see raw fuel coating the throat of the carb body or a very slight trace seeping past the float bowl gasket (nothing that would drip off, just a slight dampness).

As I've stated before, in the last few years I've experienced significantly more carb problems than in the previous 20 years.  It's got to be the ethanol and/or oxygenated additives in this piss they call gasoline these days.  

In rural Arkansas, you can still find uncontaminated fuel.  When I got back from Arkansas in June this year, I still had a tankful of good fuel left in the FZ.  It sat the rest of summer without being started and and ran perfectly when I finally got around to riding it.  Unfortunately, that tank of fuel is now gone and it's been awhile since I rode that bike.  I've got several bottles of Techron waiting to go in for my next ride on it.

Not sure any of this helps,

DavidR.

[Pat Conlon]

Ok, thanks David. So the first place I'll look will the my #42.5 pilot jets....or did you the air/fuel idle mixture screw?

[SlowOldGuy]

Good question Pat.  Not sure exactly where the clog really was.  Could have been somewhere in the circuit instead of the actual jet itself.  All I know is the Techron worked.  I have removed the tank and the idle mixture screws and shot spray cleaner directly into the idle circuit when I was too lazy to take the carbs off.  Not sure how effective that is as I now use Techron all the time. 

DavidR.

[turbocamino]

  I live near the water and not far from an airport and have friends in both fields and want to share that both the marine and aviation techs are swearing by a product i never heard of called "Star Tron enzyme fuel treatment"....i just started using it so i cant give any hard data. The boat tech said he has seen stabil gel up some,possibly due to the ethanol. Google it...there is info on it... i did put it in all (6) of my engines this fall. I always felt that if its recommended and used by the aviation and boat guys that it had to be researched before hand(especially the aviation industry). anyway, they swear by it now. pretty cheap too.

[RichBaker]

I've seen bottles of it at local dealers....  http://mystarbrite.com/startron/index.php?option=com_content&task=view&id=93&Itemid=123
haven't tried it. I have been adding marine 2-smoke oil @ 1oz/5gallons. Seems to help. Heard about that on LS1.com