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SOHC.co.uk Forums => CB750 => Topic started by: onethumb on February 05, 2016, 10:12:35 AM

Title: Green stuff in the carbs!!
Post by: onethumb on February 05, 2016, 10:12:35 AM

Hi all,

Anyone know what this is and what to do. It looks like algae but there was fuel in the chambers. Bike would start but not run. Knew it was a carb issue but this green has me scratching my head.
Thanks.
Steve. (http://uploads.tapatalk-cdn.com/20160205/ab4476eed4e172c83b91379d70d113bc.jpg)


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Title: Re: Green stuff in the carbs!!
Post by: ST1100 on February 05, 2016, 10:19:54 AM

Green/yellowish deposits origin AFAIK from substitutes (different distributors order different colour additives at the refineries), respectively in unleaded fuel... combined with other crap for that ethanol...

Title: Re: Green stuff in the carbs!!
Post by: hairygit on February 05, 2016, 12:59:47 PM

Or possibly algae growing in the water that the ethanol has absorbed.

Title: Re: Green stuff in the carbs!!
Post by: Bryanj on February 05, 2016, 05:23:05 PM

Have you been smoking something naughty in the presence of your bike?

Title: Re: Green stuff in the carbs!!
Post by: Honda Al on February 05, 2016, 05:28:10 PM

Bogies? Or is that just very immature of me?!  ;)

Title: Re: Green stuff in the carbs!!
Post by: BigAl (Alan) on February 05, 2016, 05:56:42 PM

Modern fuels have around a month long shelf life, after this time the volatile elements within it start to evaporate off and degenerate into a 'green furry residue' within the carb bowls...not my words, extract from December 'Tansha' VJMC magazine by Neil Kidby concerning problems with Ethanol & the other stuff ...very good article

Title: Re: Green stuff in the carbs!!
Post by: MarkCR750 on February 05, 2016, 10:32:17 PM

I put Sta-bil fuel stabiliser in my CR last time I ran it 4 months ago, I fired it up last week and to my great surprise it started and ran fine, I'll whip a bowl off soon and report back.
You can get stabil on eBay it's not very expensive .

Title: Re: Green stuff in the carbs!!
Post by: Greebo on February 06, 2016, 11:34:05 AM

This does the same job as the Sta-bil additive but much cheaper

http://www.ebay.co.uk/itm/Genuine-Briggs-Stratton-Fuel-Fit-250ml-992381-Stabiliser-Keeps-Petrol-Fresh-/381160532252 . single 250ml Bottle £5.83

http://www.ebay.co.uk/itm/2-x-GENUINE-BRIGGS-STRATTON-PETROL-STABILIZER-FUEL-ADDITIVE-992381-fuel-fresh-/191797188224 £10.85 for 2 250ml bottles


Part Number 992381. 250ml Fuel Fit treats up to 25 litres of unleaded fuel. Use Briggs Stratton Fuel Fitâ„¢ fuel stabilizer products to help keep your fuel fit for up to 3 years, promote quick starting,...

Title: Re: Green stuff in the carbs!!
Post by: MarkCR750 on February 06, 2016, 10:11:05 PM

Thanks Greebo I'll get that next time.

Title: Re: Green stuff in the carbs!!
Post by: onethumb on February 07, 2016, 05:42:14 PM

Thanks all.
 Now I know.
 Bike hasn't been on the road since 1998 so this is to be expected. All the float valves are bad, two of them are stuck in the closed position two have lost their bounce. David silvers is getting some of my hard earned today.

Title: Re: Green stuff in the carbs!!
Post by: MarkCR750 on February 07, 2016, 06:57:12 PM

Best to get new ones as you are doing but if you need to restore the bounce to an old one leave it in carb cleaner over night then spray carb cleaner into it whilst working it I and out, often they are just gummed up.