This one is fun. I am going to have to go back over all of the possibilities
submitted yet again.
Spark is working beautifully with no misses and both vacuum and mechanical
advance working fine on all four cylinders.
Valve lash is fine.
Fuel pump is working fine (Don't you just LOVE the Haynes procedure for
testing the fuel pump? No quantitative data whatsoever. "it should squirt
petrol every other revolution"); three mechanical pumps and an electrical
pump all present the exact same symptoms.
Carb pistons fall nicely to the bridge (H1 carbs). Balance is nice. Carb
pistons open and close in perfect unison. With no load the engine runs fine;
with a load, the engine starts to cough around 3000rpm. Float level was a
bit off on both carbs; front was too low, back was too high. Made no
difference. Ran the carbs rich and ran them lean and it made no difference.
We did not get around to removing the top bells and verifying the needle
position in the piston. Neither of us had a compression gauge, either.
How hard is it to temporarily slap a set of HS2 carbs and intake manifold
onto a 948? New intake/exhaust gasket, new set of carb-mounting gaskets,
fittings for the choke and accelerator, heatshield, what else am I
forgetting? Or does someone out there have a pair of H1 carbs sitting around
waiting for their concours restoration that they could loan Jerry?
David Lieb
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