The Ford Barn

31Abone · 01-19-2014, 10:08 PM

running single stromberg 81 on my 30 CCPU with police head,half trottle goes faster then full throttle ? using gravity feed with tank near full ..whats going on here ? SC

PC/SR · 01-20-2014, 12:00 AM

Lots of things are possible. Float level, jets and timing are the first things that come to mind but that does not mean much. Take care of the basics first. Big Pine is around 4000 feet elevation what size jets do you have?
Does "go faster at half throttle" mean the engine will not rev up past half throttle? Does it slow down? Does it miss or sputter past half throttle? Good flow from the tank? No or clean filters or sediment bowl? Any problems when it had a stock carb? What manifold and linkage? Is the carb in good shape, meaning clean inside and set up correctly? Not trying to be negative, just some things to think about. Really, more info needed for a diagnosis.

ken ct · 01-20-2014, 12:30 AM

I would agree with PC,as 81 is equipped with .035 jets and PV of #71. Don't think anything is available in smaller sizes.of PV,but might have some .033 jets id have to check them and measure the hole. 4,000' is barely at the border line of a jet change. Other than a blockage somewhere you might be better off using a jetted down 97 or a 94. What happends if you partially close the choke,gets worse carb too small,try it and let us know. ken ct.

Pete · 01-20-2014, 12:52 AM

Gravity feed won't cut it.
Those carbs like at least 2 lb of fuel pressure.

Flatout · 01-20-2014, 01:42 AM

A fuel pump and a larger carb.

hardtimes · 01-20-2014, 01:47 AM

Sponsored Links (Register now to hide all advertisements)

Hey SC,
Can you tell us what condition your engine is in, that is , recently rebuilt or old/tired ? Has the 81 been rebuilt or just off the shelf ? I believe that if your engine is in good shape, that it will handle a 97 Stromberg..or the 81 for sure.
I run two 81s (rebuilt) on my warmed up B engine. I've run with electric pump/regulator and presently run (last 6mos) with just gravity feed, but everything is tiptop condition (carbs tuned in/ clean filter/all connections TIGHT)...no problems whatsoever. Let us know more of present situation as asked.

Proper timing setting is VERY IMPORTANT !

31Abone · 01-20-2014, 02:37 AM

Single 81 in a EGGE rebuilt engine with police head..I thought maybe the 81 did not put out enough for a model A as it was design for a 60 v8 136 CI..also not sure that my fuel pressure is high enough..I did take off top of carb with gas on and bowl was full..I hate to use a electric pump but may have to in this case ..sc

01-19-2014, 10:08 PM	#1
31Abone Senior Member Join Date: Apr 2013 Location: Big pine Ca 93513 Posts: 797	running Stromberg single 81 no power at full running single stromberg 81 on my 30 CCPU with police head,half trottle goes faster then full throttle ? using gravity feed with tank near full ..whats going on here ? SC

01-20-2014, 12:00 AM	#2
PC/SR Senior Member Join Date: May 2010 Location: Santa Rosa, CA Posts: 1,285	Re: running Stromberg single 81 no power at full Lots of things are possible. Float level, jets and timing are the first things that come to mind but that does not mean much. Take care of the basics first. Big Pine is around 4000 feet elevation what size jets do you have? Does "go faster at half throttle" mean the engine will not rev up past half throttle? Does it slow down? Does it miss or sputter past half throttle? Good flow from the tank? No or clean filters or sediment bowl? Any problems when it had a stock carb? What manifold and linkage? Is the carb in good shape, meaning clean inside and set up correctly? Not trying to be negative, just some things to think about. Really, more info needed for a diagnosis. Last edited by PC/SR; 01-20-2014 at 12:17 AM.

01-20-2014, 12:30 AM	#3
ken ct BANNED Join Date: May 2010 Location: stratford,ct Posts: 5,971	Re: running Stromberg single 81 no power at full I would agree with PC,as 81 is equipped with .035 jets and PV of #71. Don't think anything is available in smaller sizes.of PV,but might have some .033 jets id have to check them and measure the hole. 4,000' is barely at the border line of a jet change. Other than a blockage somewhere you might be better off using a jetted down 97 or a 94. What happends if you partially close the choke,gets worse carb too small,try it and let us know. ken ct.

01-20-2014, 12:52 AM	#4
Pete BANNED Join Date: May 2010 Location: Wa. Posts: 5,423	Re: running Stromberg single 81 no power at full Gravity feed won't cut it. Those carbs like at least 2 lb of fuel pressure.

01-20-2014, 01:42 AM	#5
Flatout Senior Member Join Date: May 2010 Location: Damascus Oregon Posts: 160	Re: running Stromberg single 81 no power at full A fuel pump and a larger carb.

01-20-2014, 01:47 AM	#6
hardtimes Senior Member Join Date: May 2010 Location: South California Posts: 6,190	Re: running Stromberg single 81 no power at full Sponsored Links (Register now to hide all advertisements) Hey SC, Can you tell us what condition your engine is in, that is , recently rebuilt or old/tired ? Has the 81 been rebuilt or just off the shelf ? I believe that if your engine is in good shape, that it will handle a 97 Stromberg..or the 81 for sure. I run two 81s (rebuilt) on my warmed up B engine. I've run with electric pump/regulator and presently run (last 6mos) with just gravity feed, but everything is tiptop condition (carbs tuned in/ clean filter/all connections TIGHT)...no problems whatsoever. Let us know more of present situation as asked. Proper timing setting is VERY IMPORTANT ! Last edited by hardtimes; 01-20-2014 at 01:48 AM. Reason: ...........

01-20-2014, 02:37 AM	#7
31Abone Senior Member Join Date: Apr 2013 Location: Big pine Ca 93513 Posts: 797	Re: running Stromberg single 81 no power at full Single 81 in a EGGE rebuilt engine with police head..I thought maybe the 81 did not put out enough for a model A as it was design for a 60 v8 136 CI..also not sure that my fuel pressure is high enough..I did take off top of carb with gas on and bowl was full..I hate to use a electric pump but may have to in this case ..sc