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Sat Jun 06, 2020 8:36 pm

have a 1915 with dual Dellorto 40 DRLA. It runs good but have a horrible time to start. Have Bosch blue coil, new wires, points on the Bosch 009 and NGK spark plugs. I changed the points and it helped a little. Carbs were properly jetted. Engine had a break-in and valves re-adjusted. It seems that gets flooded by too much pumping gas with the accelerator. I will clean the spark plugs tomorrow. Anything else? any ideas? :oops:

Sat Jun 06, 2020 11:19 pm

I'd check heat range and plug gap, then recheck engine timing.

Sun Jun 07, 2020 12:09 am

Step 1push down once fully on accelerator peddle then let peddle come back up to 1/4 open position step2 turn key without moving from the 1/4 open position.
Repeat step 1&2 when engine stalls until engine no longer stalls.

Sun Jun 07, 2020 12:52 am

In my experience the smaller the idles, the harder it will be to start and I find when I have my AFR on the lean side for mileage they are well into the hard to start range. In fact in the winter it's almost impossible. That's the conundrum. I have my pumps turned down to the minimum to stop the stumble and it starts best after 3 or 4 presses.
Another possibility is your carbs need priming - fuel deep enough for the pumps on the floor of the bowl isn't the same as floats at max.

Sun Jun 07, 2020 5:24 am

Zed999 wrote: In my experience the smaller the idles, the harder it will be to start and I find when I have my AFR on the lean side for mileage they are well into the hard to start range. In fact in the winter it's almost impossible. That's the conundrum. I have my pumps turned down to the minimum to stop the stumble and it starts best after 3 or 4 presses.
:roll: :roll:

The real conundrum lies with a VW performance industry and it's promoters that have set cold starting technology back to the early 1900's! But don't take my word for it, do a search on Wikipedia for "carburetor choke valve" and it will be explained.

Sun Jun 07, 2020 7:01 am

oprn wrote: Zed999 wrote: In my experience the smaller the idles, the harder it will be to start and I find when I have my AFR on the lean side for mileage they are well into the hard to start range. In fact in the winter it's almost impossible. That's the conundrum. I have my pumps turned down to the minimum to stop the stumble and it starts best after 3 or 4 presses.
:roll: :roll:

The real conundrum lies with a VW performance industry and it's promoters that have set cold starting technology back to the early 1900's! But don't take my word for it, do a search on Wikipedia for "carburetor choke valve" and it will be explained.

Being in the UK it annoys me that someone previously removed the cold start from my dells.

Sun Jun 07, 2020 7:38 am

Just another case of what's right for the southern California drag racing scene is right for the rest of the world. It's not easy to find unmolested performance carbs these days but when you do treat them like gold! I love mine.

Sun Jun 07, 2020 3:39 pm

Great comments! I just checked spark plug 1, full of carbon. Black as hell.

I am using NGK-BR6HS is that the correct heat range for my engine?
Please let me know if I need to get other spark plugs.

Thank you all, great ideas that I will use. FYI I am also using a glass fuel filter and I see the fuel pump is flowing. It also smell like gas so carbs might be flooded a little.

BTW engine is in a 1969 912. Just moved the car a little to put it in a trailer for painting and looks to have good power.

Thank you all in advance,

Jose

Sun Jun 07, 2020 3:55 pm

Your plugs are about mid rage, maybe one step cold.

What heads are you running? Are you sure your not using 1/2" reach plugs in a 3/4" plug reach head?

Sun Jun 07, 2020 4:12 pm

sorry, I am using stock valves 043 German heads, ported and polished, enlarged intake and exhaust holes. 14mm 1/2 inch spark plugs

Sun Jun 07, 2020 4:14 pm

airjose wrote: sorry, should have been more specific. I am using stock valves 043 German heads, ported and polished, enlarged intake and exhaust holes. 14mm 1/2 inch spark plugs

Sun Jun 07, 2020 4:28 pm

airjose wrote: sorry, I am using stock valves 043 German heads, ported and polished, enlarged intake and exhaust holes. 14mm 1/2 inch spark plugs

Well the plugs are probably about right then. You could go with the same plug without the "R" (resistor) but IDK what kind of difference that would make.

If you feed the carbs a bit of gas from a pipette or something then try to crank it up, will it fire right off? Try to narrow down if it's a fuel supply issue.or a ignition issue

Sun Jun 07, 2020 5:38 pm

These spark plugs do not have a lot of hours but they look awful. If a go a step down as a hotter plug, what spark plugs should I use? keep the same B6HS? will get new spark plugs and then try a little gas on the venturies and other tricks that you all tell me to experiment.

Sun Jun 07, 2020 5:42 pm

airjose wrote: These spark plugs do not have a lot of hours but they look awful. If a go a step down as a hotter plug, what spark plugs should I use? keep the same B6HS? I will get new spark plugs and then try a little gas on the venturies and other tricks that you all tell me to experiment.

Sun Jun 07, 2020 5:52 pm

The next hotter plug for an NGK would be the B5HS or BR5HS. This would actually be the correct standard heat range for a Type 1 engine.

Sun Jun 07, 2020 6:10 pm

should I go with a hotter spark plug?

Sun Jun 07, 2020 6:38 pm

If you're going make a change, try the B5HS. One step hotter and non; resistor.

If you find that you are racing it when you get it going well, you can go back to the 6 if needed.

Sun Jun 07, 2020 7:35 pm

Thank you guys, will clean the BR6HS and use them for a little while, then go with the hotter B5HS; NGK site says was replaced by BR5HS. I will use all of your ideas since it just takes to long to start.

Thanks again to all,

Jose