10 replies to this topic

[2009poolesparky]

Trouble starting and then when eventually running, erratic idling up and down.

A series engine (in a 1980 saloon)

Hi everyone, have just finished transfering a good engine that was running fine from a shot shell to a good shell, but now she won't start easy and when it does it's a right mess.

ok so the engine is a standard 998cc A series (with solenoid mounted on inner wing rather than on starter)

HS4 carb with a needle that has AAC stamped on it, new needle valve and gasket on the float bowl.

Lucas 59D distributor with brand new condenser, points gapped at 0.4mm and brand new rotor arm, cap ht leads and plugs.

standard cast inlet/outlet manifold with a bog standard 1 silencer box exhaust.
standard plastic air filter box

I got it running, disconnected the vacuum advance pipe and set the timing at 8 degrees BTDC.


next thing is confusing me...

the car tick over is way too high, I can't determine exactly as I don't have a rev counter, but i'd say it's in the range of 1500 - 2000 rpm.

when you try and accelerate it tries to stall / does stall. other times at tick over it will just stall.

the idle tick over screw is wound right out.

after the car has stalled it is very difficult to start, with or without choke it does not like it.

there are no leaks around the inlet manifold, and the compression in the cylinders is good.




the engine ran fine, if a little high at tick over before i took it out of the other car. the only difference was that it had an RC 40 exhaust on it then with a separate alloy inlet manifold and an LCB.


sorry for the essay (it does say be in depth lol)

if any of you can help that would be great.... it's really confusing me this one and my girlfriend wants her car back now, so i have to find a solution asap!

thanks


alex



Any non-standard parts that might be involved with the problem?

[2009poolesparky]

the dashpot is topped up with oil too...

[lrostoke]

Was the timing set with a timing light ??

8 BTDC @ 1500 is a fairly standard setting for a later 998.

What about mixture have you set that, is the carb the one that was on the engine when it had the RC40 fitted ??

[2009poolesparky]

yes i timed it up with the strobe light with the vacuum pipe disconnected.

the carb is the same one that was on the engine before i put it into this other car and it worked fine with the rc40 fitted


alex

[lrostoke]

Suprised that AAC needle worked with the RC40 and alloy inlet, AAC is just a standard needle to weak for the other set up.

Could be a mixture problem, I'm guessing they had to have that carb set rich to run that needle.

[2009poolesparky]

ok so here goes..

after some further investigating i have found the following:

fuel pump is working, fuel is being delivered to the float bowl however it then just stays there and does not appear to get used as i crank over the engine, even with the choke fully out! i checked this by filling the float bowl with fuel, then removing the top of the bowl and holding the float up to stop the fuel coming out, then cranking the engine over the fuel does not go down and the engine does not fire....
... after draining the bowl manually i took the jet out and blew through the jet which would have got any debris out. re assembled and tried again.... still no luck. to confirm this, if i pour a tiny amount of fuel directly into the carb air intake it will fire upand run fine. as it runs out of fuel the revs seem to increase quickly, before finally the engine dies - similar properties to the erratic revving as i experienced when the engine used to run.

any ideas now? i dont see why i would need a new jet, as it is not blocked and doesnt leak. maybe the needle, however it still should work if i pull out the choke. somehow the fuel is not getting from the float bowl into the carburettor.....


alex

[lrostoke]

Have you checked for dirt in the bottom of the float and also the pipe that joins the float to the jet. ??

[2009poolesparky]

Checked for dirt in the bowl but that is clean
The pipe I flushed with carb cleaner spray so I guess it is clean..

Just thinking could it have the wrong jet fitted? It looks newer than the rest of the carb, it is a red plastic bodied one...

I have a spare hif 44 which I might try,but do you think that would suit the engine?


Alex

[lrostoke]

From what you describe..

Which if Im right is basically a standard engine.

standard inlet and exhaust now, AAC needle should work ok.
If thats the carb that was on with the alloy and rc40 though I can't see how it would run right unless its readjusted for the new set up.

[2009poolesparky]

yes, how should i adjust it, i have tried it richened up and weaker... everything seems to be as it should.

i set the jet to the factory setting, which as far as i believe is all the way up so that the top of the jet is flush with the bridge in the carb, then 2 full turns to loosen it off. it appears that it is not sucking the fuel through the jet and jet hose.

i have a spare jet off another hs4 carb, not sure how good it is.

will give it a try tomorrow and let you know how i get on, thanks for all the help so far too.


alex

[2009poolesparky]

GOT THE BUGGER!

the o seal between the float bowl and the jet pipe and been crushed over the end of the pipe! looked pretty worn too.

new one fitted, starts first time and runs perfect!

thanks for all the advice aswell guys!





alex