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Overflowing float-bowls...

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Yoda
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Yes, it's an old problem, but I seem to have it. I've got dual HS2s (on a 1275) and it seems that they intermittently overflow (sometimes one, sometimes both). I've taken them apart for what seems like a zillion times, but no luck. The Grose-jets are new (and seem to work well during testing) and I'd rather not jump to Viton tips for now. The floats are fine and are properly adjusted. I've also removed any crude in the bowls and the fuel is filtered. I have a nearly new SU electronic fuel pump.

Aaaargh. :cryin:

So, what else might I check? Also, with an SU pump, should I consider a pressure valve so-as to better dial-in a limit? Bill (to the north of me) said that even his Joe Curto rebuilt carbs did this and he solved it with a Holly regulator. I would have presumed that an SU pump wouldn't over-pressurize. If I go that way, are there various regulators to consider?

Thanks.
 
The standard SU pump should deliver the correct pressure, somewhere between 2-3 PSI. With a stock pump you should not need a regulator.

You did say they were Grose Jets and that you did not want to switch at this time. If you installed the jets, did you clean them prior to installation? There have been accounts on various boards that the jets have a Cosmoline like substance inside to keep the ball bearings from corroding. Those threads say that you need to use a more aggressive solvent than gasoline to remove the coating before putting the jets into service. I have heard of people washing the jets with spray carb cleaner, acetone, and lacquer thinner. Anyway, if you did not clean them prior to installation I would start with that. While you are in there, make sure the jets have a fiber washer to seal them to the float bowl lid.
 
Boink said:
The Gros-jets are new (and seem work well during testing) and I'd rather not jump to Viton tips for now.
Aaaargh. :cryin:
Thanks.
Click to expand...

I doubt it's the pump. Overflowing float bowls are almost always a problem with the needles.

I have experienced and heard many complaints of sticking Grose jets. I'd look to those for your answer.

Here's just one thread on the subject:
 
Thanks Doug and Gerard.
I've heard of this problem over the years, and thanks for the additional thread Gerard.
I think I'll take the Grose jets out and fully apart (since I didn't put them in), and then thoroughly clean them. I didn't know about the coating that might be on the ball. Perhaps this should be called Gummy-Ball Syndrome. :yesnod: ["What we have here is a particularly bad case of Gummy Ball Syndrome. Clean 'em with this elixer and you'll be back on your feet and the road before you know it."] They sure seemed operational when I tested them but I suppose they HAVE to be the problem. Again, it's intermittent (though often), so maybe that ball is sticking on occasion.
I agree about the SU pump shouldn't be a cause (given the low pressure it produces), though I think I may install a secondary filter just to be safe from crud. The floats are a bit older but they seem good... but maybe I might also swap those out (to complete the carb rebuilds).
Thanks again.
 
I had similar problems with my 1275 fuel system a while back. I got a 74 micron filter that fits the inlet on the SU pump from the tank and then a Holley low pressure regulator and another filter just before the front carb on my factory twin HS2 carbs,set at 2.6 lbs of line pressure-Have had no problems ever since. I think Holley part number 12-804 is the low pressure regulator
 
reddsprite said:
I had similar problems with my 1275 fuel system a while back. I got a 74 micron filter that fits the inlet on the SU pump from the tank and then a Holley low pressure regulator and another filter just before the front carb on my factory twin HS2 carbs,set at 2.6 lbs of line pressure-Have had no problems ever since. I think Holley part number 12-804 is the low pressure regulator
Click to expand...
Thanks. That'll be plan "B." :yesnod:
 
I personally would make plan B a change over to viton tipped needle jets. Cheapest route as well. I have never had good luck with the gross jets and I know I'm not alone. I know there are those who swear by them but I always did it at them!!


Kurt
 
nomad said:
I personally would make plan B a change over to viton tipped needle jets. Cheapest route as well. I have never had good luck with the gross jets and I know I'm not alone. I know there are those who swear by them but I always did it at them!!
Kurt
Click to expand...

Seems like there are these 2 schools of thought on the float valves (Viton vs. Grose). My understanding is that the NEW (and improved?) Grose-jets are fine. I'll give 'em one more shot before cursing at them and flinging those balls at a passing dog owner that fails to pick up after their pooch... and then changing to Vitons.
Thanks. :smile:
 
Get rid of the Grose jets, and I bet your problem goes away, these were a decent product 25 years ago, but as of late they mostly are the incorrect size, fouling up the float level, and generally cause leaks, this is coming from a guy who rebuilds SU carbs for a living, and I would never, ever use a grose jet.
 
I have never seen "new and improved" Grose jets. What I remember is that the original Grose jets used to be fine when they were produced by a family business. I don't remember hearing of or experiencing problems with them until the company was taken over by a larger firm.

I am in the anti-Grose league but won't discourage you from using what you have at the moment. I have had Grose jets stick open causing flooding AND I have had them stick closed so I couldn't start the engine. I have removed them from my Triumphs and my Mini in preference to the Viton tipped needles.
 
Remember that there are also needles that are "non-viton" tipped and avoid those along with the Gross Jets! Be SURE that there IS some rubber on the tips! The brass tipped ones don't seal well either.
BillM
 
OK OK... :laugh: I've ordered Viton-tiped ones. :yesnod: You've all convinced me. An easy thing to swap out and try.
Thanks again.
 
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