CU non-starter - engine solid

[81AirCooled]

E D I T; After going through the list below I got some nasty backfiring before the fuel in the carbs was all burned off - any idea what could cause backfiring like this;

http://youtu.be/jsvSnmMr6W0" onclick="window.open(this.href);return false;

John (Sarran1955) has been an absolute star rebuilding the engine after my own moronosity cracked the case. I managed to get the engine back in the van today after a bit of struggle getting it nicely lined up to the autobox. Found a live wire for the new 034 svda dizzy, put 5 litres of fresh fuel in and tried to start her up. I was dead relieved that she turned over but I just couldn't get her to fire up.

It's looking a lot like fuel starvation according to my helper so what's the checklist I need to run through?

- put a thimble full of fuel in each carb to get her running long enough to suck fuel?
- check fuel is getting to the pump? How's the best way to do that?
- check filter is clear
- check fuel tank breather - is that just a hose on the filler neck or do I need to look elsewhere?

After 10 hours working on the engine today I'm definitely giving it a rest until tomorrow

[sarran1955]

Hello,

The video is a good idea..

The engine should be 'plug'n'play..

Just 12 volts and connect up the throttle and fuel line..

Firstly,are you getting petrol through the pipe from the tank to the pump (via the filter)

I ask because 5 litres may not be enough if the tank was really empty.

A thimble of fuel will start the motor..should be enough for the pump to fill the carbs.. maybe 2 goes..

It will spit and pop..well if someone poured petrol down your intakes,,you'd do the same..

Then once primed, it should start and run properly.. with the aircleaner on please..

I set the engine up so you could run with out the air inlet vacuum (painted tinlid over the preheat air entry), with the rubber ring/seal.

The blanked 4 mm tube feeds the vacuum control on the balancer pipe, and the blanking screw on the back of the air filter comes off , and the pipe from the preheat fits in its place..

But get the fuel right first..

Nearly there....

Cordialement,

[81AirCooled]

Thanks John, I'm going to attack this as planned and sort out the fuel issue as like you say there should be no problem with the timing/air leaks etc.

The van has been out in a field for nearly 12 months now so I suppose it's possible the fuel lines/filter may have had some moisture condense in there. Will buy a new fuel filter asap and blow back through the fuel hose to clear out any possible blockage and take it from there.

[BOXY]

Are you sure the HT leads are right, it's hard to see from the video. The flames out the top of the carb make me think that the plug is firing on the inlet stroke instead of the compression stroke. Flames out of both could be two leads on the wrong plugs maybe?

[81AirCooled]

I've checked the Ht leads and all is fine as expected. I've decided to sort the fuel starvation issue first so changed the filter and cleared the fuel hose from the pump to the tank but either the battery is flat or I've got an electric issue. Battery is charging overnight so I'll try it again before work. If it's still a dud I'll disconnect the positive to the coil as that's the only thing I could have got wrong and try again in the evening.

Worst thing is though.............. there's a bloody oil leak

[81AirCooled]

Went back this morning before to check start - nothing, just like the sound of a dead battery. Tried several batteries with all the same result. This doesn't make sense to me because after the starting issues the weekend as on the video non of the electrics have been touched.

I get another couple of nights before I have to have the van moved when I'll have it dragged either back home or into a garage.

[Ulyman]

I had a similar 'dead battery' issue at the weekend, even though I knew the battery was good.
Turned out to be the main earth path from the engine to the chassis. I put a jump lead from the starter mounting bolt to a good chassis earth, and it fired up instantly.
Might be worth a try. I don't know if that would lead to your running issues though, but you never know.

Good luck,
Mike.

[81AirCooled]

Thanks Mike, maybe the earth has come loose near the alternator. I'll check that first thing tonight.

[BOXY]

Check the spade connector to the solenoid on top of the starter motor as well.

[81AirCooled]

Still no luck. Cleaned earth at battery terminal and at the chassis/gearbox earth strap with zero effect. Disconnected, cleaned and reconnected the terminals an the starter motor with the same result I.e. none.

There's a couple of curious issues.....it's not totally dead I can actually hear the starter motor trying to turn so it's getting electricity and after only a couple of tries the strap at the battery negative terminal is warm to the touch, is that normal?

thinking out loud a bit here but what I don't understand is it going from the above in the video to not turning over at all without actually altering anything. Could the starter motor be fried from those few start attempts/could it not be engaging or is it even possible that the engine could have seized from backfiring?

[BOXY]

Take the basket off the fan and try turning the engine over with a socket on the nut in the centre. Even with the plugs in you should be able to turn the engine.

[81AirCooled]

Take the basket off the fan and try turning the engine over with a socket on the nut in the centre. Even with the plugs in you should be able to turn the engine.

Cheers Boxy, it didn't occur to me until I got back home as it's extremely unlikely but I'll just check that on Friday.

[81AirCooled]

Finally got back home, had a shower and have a glass of IPA in front me. Sadly though still no result with the van. Had the starter off the van and hooked that up directly to a battery and it runs fine "like new" the other guy with me said. Put it back in the van and it's just maybe got half a slow turn and that's it. If I hook a battery again directly to it the van still won't start but the starter is definitely getting more juice as it does seem to turn a couple of times. The previous owner had some kind of strange setup with a big cutoff switch next to the chemical loo so I'm going to have to ask someone to take a look at the electrics and how that's all set up

[BOXY]

How did you get on with turning the engine over by hand? My engine has got solid lifters and if I set the tappets to touching plus a turn the engine won't turn over. Set them to 6 thou and the engine runs fine. I know your engine has just been rebuilt but a slow turn over and the blowing back through the carb looks like a valve issue. On Sarran's vid of the engine running on the bench there's no sign of any blowing back through the carbs. Can you compression check the engine?

[81AirCooled]

Cheers Boxy, I can turn it not easily though but isn't that to be expected with the plugs in? At the moment I'm at a loss why I can''t even get the starter to turn over when it was firing literally from one day to the next without anything being touched.