3B fault diagnosis? (1 Viewer)

[KIWIALEX]

Evening. Recently iv got my 3B started that I acquired about 6 months ago. Got a few things I’d some opinions on so these are the things in noticed.

There’s only a bit but visible exhaust coming from the intake manifold

It idles ok(ish) but when given throttle there’s a clapping or knocking sound

And iv only really started it a handful of times but It does have trouble getting started / staying running (we ran in down a hill in gear as batteries (24v) were flat) it would “run” but as soon and clutch pedal was depressed it would stop (fuel lines were bled and it was getting fuel)

Any help would be greatly appreciated

 

[Eurasiaoverland]

Sounds frankly like a clapped-out engine.

How does exhaust come out of the intake manifold? Are you running it without any intake hoses from the air filter? I assume it's an old 3B (with pushrod covers under the exhaust manifold) in which case it has no crankcase vent into the intake. So it might be poor valve adjustment or valve seating. Does the engine turn over smoothly with a breaker bar on the crank bolt, or are there tight spots?

Knocking under acceleration is bad... does it have any oil pressure?

Has the engine been compression tested?

 

[OTBT]

sounds to me like there is a valve timing issue, and the venturi lines are reversed. Did you line up all the timing marks on the camshaft, crank, idler and injection pump when you re-assembled ? The clanking sounds like the wrong valves are opening and hitting the tops of the pistons - you may wish to remove the head and check to see if you toasted the pistons.

 

[Dougal]

Got leaking valves and gaskets?

I'd say it's academic at this point. It needs a strip down to see how worn out it is and likely a full rebuild.