HS2 fuel overflow
Created by: onetim
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Last post: Mar 27, 2024 Member since:Aug 14, 2002
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Quote:
Originally Posted by dklawson
Dan, I thought perhaps it was you who years ago mentioned sticky float needles. Whoever it was, I believe their advice was to take the new needle and burnish its "corners" lightly which would change the fit just enough so the needle will seat properly. I had to use that method recently when fitting a replacement carb to one of m lawn mowers. Its float valve was hanging open until I dressed the corners of the needle.
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Sorry... I did not notice people were continuing to post to this thread and that John had asked about sources for the low pressure Holley regulator.
I don't like the pancake regulator because the numerical values cast into its parts are not accurate to the point of being a problem. You need to at least temporarily fit a pressure gauge to set its delivery pressure accurately". I also don't like the pancake regulator's large internal diaphragm which burst on one of our cars. My experiences are not unique.
The Holley low pressure regulator is their part number 12-804. You should find that by Googling. You can also find it at Amazon by following the link below.
https://www.amazon.com/Holley-HOL-12-804-Pressure-Regulator/dp/B00029JC6M/ref=sr_1_4?dchild=1&keywords=holley+regulator&qid=1588947494&sr=8-4
Dan, I thought perhaps it was you who years ago mentioned sticky float needles. Whoever it was, I believe their advice was to take the new needle and burnish its "corners" lightly which would change the fit just enough so the needle will seat properly. I had to use that method recently when fitting a replacement carb to one of m lawn mowers. Its float valve was hanging open until I dressed the corners of the needle.
I don't like the pancake regulator because the numerical values cast into its parts are not accurate to the point of being a problem. You need to at least temporarily fit a pressure gauge to set its delivery pressure accurately". I also don't like the pancake regulator's large internal diaphragm which burst on one of our cars. My experiences are not unique.
The Holley low pressure regulator is their part number 12-804. You should find that by Googling. You can also find it at Amazon by following the link below.
https://www.amazon.com/Holley-HOL-12-804-Pressure-Regulator/dp/B00029JC6M/ref=sr_1_4?dchild=1&keywords=holley+regulator&qid=1588947494&sr=8-4
Dan, I thought perhaps it was you who years ago mentioned sticky float needles. Whoever it was, I believe their advice was to take the new needle and burnish its "corners" lightly which would change the fit just enough so the needle will seat properly. I had to use that method recently when fitting a replacement carb to one of m lawn mowers. Its float valve was hanging open until I dressed the corners of the needle.
Doug L.
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I went through a similar exercise years ago while trying to get a HIF44 (two differnt ones, including a brand new one) to stop drowning my engine. I started with the original mechanical fuel pump, went on to a Facet pump with a Holley regulator (and gauge!) as in this photo. Still had problems. Switched the pump for a proper SU electric pump and still had problems. I finally raced the issue to the fuel inlet valve needle being just a hair too big - when it warmed up in the brass seat, it would expand just enough to stick open. Now I only have a fuel filter in the engine bay and the SU pump in the rear subframe, and no trouble since.
.
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I went to the Holly site, and their part is all blingy chrome, but they sell an off brand that’s not chrome, but made by Holly, and is exactly the same otherwise from www.QuickFuelTechnology.com part # 30-804QFT. It’s set at 3 PSI as delivered.
I was able to install it with some modification to the supplied bracket, behind the stiffening wing below the wiper motor without modifying the LHD car. I have only bounced it down the road a few miles, but have had no flooding issues so far. I will post some pic of the install soon.
I was able to install it with some modification to the supplied bracket, behind the stiffening wing below the wiper motor without modifying the LHD car. I have only bounced it down the road a few miles, but have had no flooding issues so far. I will post some pic of the install soon.
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Quote:
Originally Posted by dklawson
I did a quick read over what you've tried so far. You said you bought new float valves from Seven. Did you buy the metal tipped ones or Viton (rubber) tipped ones? If you bought kits with all metal parts I would try again with the Viton tipped needle (Our host's part CA90).
I mentioned earlier that pressures above 3 PSI can (but won't necessarily) result in overflowing fuel. Once you get above 3.5 PSI there is a greater chance of the pressure opening the float valve. You can try several things.
1) Set the float "lower" so there is more force against the needle when the bowls fill and floats rise.
2) Fit an electric pump (Facet brand) with a max output of 2.5 PSI.
3) Fit a low pressure fuel pressure regulator (Holley brand... not the chrome pancake bling part in the parts stores).
I mentioned earlier that pressures above 3 PSI can (but won't necessarily) result in overflowing fuel. Once you get above 3.5 PSI there is a greater chance of the pressure opening the float valve. You can try several things.
1) Set the float "lower" so there is more force against the needle when the bowls fill and floats rise.
2) Fit an electric pump (Facet brand) with a max output of 2.5 PSI.
3) Fit a low pressure fuel pressure regulator (Holley brand... not the chrome pancake bling part in the parts stores).
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Yes I did see one for 0 thru 10 psi and one for 0 to 5 set at 2.7 as delivered, thanks.
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If you order the Holley regulator, make sure you get the one for lower pressure. The "normal" one is for pressures higher than what the SUs can handle. Try to achieve a setting close to 2.5 PSI.
Doug L.
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Thank you for the tips, I have the facet pump from my original setup but I can’t stand the woodpecker noise, or really any ticking sound, clocks included. I will order the Holly regulator. Thanks again.
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I had these same problems with HS2's on the 1275 for years. Tried all things mentioned above and this problem would still happen on and off. Got so bad that I suggested to my wife that she ride with the fire bottle in her lap. Ended up driving solo! Finally bought the Holley pressure regulator mentioned above and an electronic pump, set the regulator at 2.5 PSI, and I have not seen a drop of leak in the 20 years since.
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I did a quick read over what you've tried so far. You said you bought new float valves from Seven. Did you buy the metal tipped ones or Viton (rubber) tipped ones? If you bought kits with all metal parts I would try again with the Viton tipped needle (Our host's part CA90).
I mentioned earlier that pressures above 3 PSI can (but won't necessarily) result in overflowing fuel. Once you get above 3.5 PSI there is a greater chance of the pressure opening the float valve. You can try several things.
1) Set the float "lower" so there is more force against the needle when the bowls fill and floats rise.
2) Fit an electric pump (Facet brand) with a max output of 2.5 PSI.
3) Fit a low pressure fuel pressure regulator (Holley brand... not the chrome pancake bling part in the parts stores).
I mentioned earlier that pressures above 3 PSI can (but won't necessarily) result in overflowing fuel. Once you get above 3.5 PSI there is a greater chance of the pressure opening the float valve. You can try several things.
1) Set the float "lower" so there is more force against the needle when the bowls fill and floats rise.
2) Fit an electric pump (Facet brand) with a max output of 2.5 PSI.
3) Fit a low pressure fuel pressure regulator (Holley brand... not the chrome pancake bling part in the parts stores).
Doug L.
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Well I Have the Mini out of storage, and all is well other than a return to this flooding/fuel dumping issue. I have narrowed the situation where this occurs to bumpy 25 mph roads. Think 50 year old neighborhood concrete roads, lots of sharp jarring jolts. Hooked up a pressure gauge and at idle show 4 psi, limits at 4.25 psi at all speeds Higher. On shutdown it holds 3.5 for at least 5 minutes. Too high?
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So, I changed all the rubber fuel lines, new filter now just before the left carb inlet, Cleaned the fuel bowls, the jets, passages, and hard line. This time I filtered the collected cleaner/fuel, put my readers on, and sure enough small bits of black. I could see nothing in the old filter that was before the pump, I will keep an eye on the new one after the pump. I split in half the old fuel lines, the long way, and could not see any damage. Could be the diaphragm in the pump is starting to come apart, I do see they can be purchased and replaced. All is good at the moment. Thanks again.
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Will do, and I will post back, thank you for the advice.
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Quote:
Originally Posted by onetim
... feeding the fuel pump.
Place the filter right before the carbs in a location where it can be easily seen and accessed. When/if you relocate the filter, replace all the old rubber lines AND blow through the hoses, pipes, and float valves. Make sure no debris is present.
Doug L.
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I like the fuel line idea, it's only 4 years old, but I will replace. In the pic with the valve cover you can see the filter below the fuel bowl, feeding the fuel pump.
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Quote:
Originally Posted by onetim
What’s an expected or reasonable pressure range, 4 to 9 psi? For twin HS2s
If a mechanical pump fails it will give you less pressure, not more. Flooding (or carb overflow) will not be because of your mechanical pump.
In your earlier pictures it was unclear if you have a fuel filter in the engine bay before the carbs. If not, install a translucent filter before the carbs and replace all the rubber fuel lines after the filter with new. Old hoses can shed crumbs of rubber when you handle them. Those crumbs can get into the float valves and hold them open.
Also check the float valves again. Make sure they can move up and down freely without binding.
Doug L.
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Drove 40 mile out to Pops house no problem. Drove 35 miles back and turned it off for five minutes, went one more mile and loaded up to where it would run but not go, pulled in a lot and dumped a quart or more of fuel before it stopped. I was tapping on the bowl, turning off and restarting but can’t say what stopped it. Then ran out of gas a half mile from home. Added gas then added 3 gallons with no more excitement Beginning to trust that it’s not needles, seats, or floats. So fuel pump? Running a factory mechanical pump of unknown age on a 89 1275 A+ I have no pressure regulator. Thinking the next step is to tee in a pressure gauge. What’s an expected or reasonable pressure range, 4 to 9 psi? For twin HS2s
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Hmmm, started leaking fuel from the right carb occasionally as well. Purchased new black adjustable floats, and new needle/seats from 7. Beyond the float differences, the new purchased needles are a triangle in shape, as opposed to square, neoprene with no internal buffer. A problem or mistake is that the seats did not come with any gaskets, but the floats came with every kind of lid gasket/seal. Glad I have a bunch of service manuals, only the old Orange Hanes manual gave the float setting procedure.
Back to no leaking again, getting out for a long drive today, fingers crossed.
Back to no leaking again, getting out for a long drive today, fingers crossed.
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Thanks for the pictures.
If both bowls have a fuel level about the same as shown in the one picture you are in good shape as far as the carbs won't overflow. Perhaps you had a crumb of old rubber hose that needed to work its way through the plumbing and past the float valves.
The black floats are not phenolic. They are a "softer" nylon-like plastic like the original ones and are sold by Burlen/SU as "Stay Up" floats (resistant to fuel additives). I don't think your carbs would have come from the factory with brass floats. I think brass was replaced by metal/plastic when the HS series carbs started replacing earlier "H" series carbs.
If both bowls have a fuel level about the same as shown in the one picture you are in good shape as far as the carbs won't overflow. Perhaps you had a crumb of old rubber hose that needed to work its way through the plumbing and past the float valves.
The black floats are not phenolic. They are a "softer" nylon-like plastic like the original ones and are sold by Burlen/SU as "Stay Up" floats (resistant to fuel additives). I don't think your carbs would have come from the factory with brass floats. I think brass was replaced by metal/plastic when the HS series carbs started replacing earlier "H" series carbs.
Doug L.
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