I'm wondering is there was some kind of 'heat soaking' in the carburetor simply due to its elevation in the engine compartment - that is why the car seemed hard to start - maybe. This formulation means that summer blends are 'harder' to vaporize than winter blends.( high VP - high vaporization, low VP - low vaporization) Since ethanol vapor pressure is consistent and it's amount ( 10%) is the same summer to winter, that implies the gasoline portion is 'different'. IN Pennsylvania, The federal government standard during summer months is a RVP ( Reid Vapor Pressure) of 7.8 versus a winter blend of 9.0. There is Ethanol addition to almost all the fuel I had/have access to. It generally does seem to help but the slower starting is a problem and confusing - any thoughts? I think the car needs re-tuned to run the diesel addition - but how?. Use of the electric pump all the time seems to flood the engine after I stop ( especially after running for some time) I can hear the electric pump running and then it sounds like ( after say 7 seconds) to start to dead-head. polish the copper entering the pump ( better reflection? lower emissivity?), add more insulation, go to 10% diesel. Some suggestions from some folks on the tour: change the line from copper to SS. With the higher percentage diesel in the morning with a cool engine, it seemed to have a periodic misfire that disappeared after about 5 minutes, medium to high throttle and then warm engine. Almost ALWAYS fired irregularly but cleared after 7-10 seconds to consistent cylinder firing. Almost AWLAYS needed to choke it AND use about 1/4 foot throttle to start. Starting was always hard so I started to pour a little water on the fuel line to carburetor ( I have it insulated and assumed that the water-soaking would result in transpirational cooling - alas, still hard start). Friends told me they did not see smoke at any time from 5-7 to maybe 3ish%.īy day four, I was really tapering off the diesel addition shooting for 3-4ish% I just was getting frustrated with the harder starting.Īdditional measures after any run then tour stop was to open hood to aid cooling AND pour a little water on the fuel pump. Observed another car using 10% diesel - and significant exhaust smoke. During the heat of the day, the car was hard to start - it would fire on a cylinder or two then require chiocking to get it to start and it was almost always irregular - not all cylinders firing then cleared to all cylinders firing in 10-12 seconds. So decided next iteration was back to 5%. Increased diesel to ~7%.Īfter ~7%, starting was a little 'harder'. Continued harder starting or rather slower starting - typically, it fires on the first few revolutions of starter. I have NOT yet examined spark plugs.ĭay 2 - higher temps by a degree and one instance of vapor lock - with ~5% diesel AND cleared by use of electric pump.
That afternoon I added about a 5% addition of diesel - ( temps about 92), I did have some difficulty starting the hot engine ' hot start' then carburetor vaporization?Īfter diesel addition, and the next morning especially, the car was a little harder to start. I did have some increased temperature but not severe over-heating.
On day one after a long climb, the Chevy started to vapor lock and the use of the electric fuel fixed the solution but as soon as I cleared the vapor locking, I then turned off the pump. The tour did not have excessive long runs ( >30 miles at a clip) and only several fairly long hills ( 5% grade for about 1 mile). Conditions were tougher - daytime temperatures were 90 to about 93 with humidity varying.
Small engine vapor lock update#
Well, an update of conditions and observations.
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