Starting Problem

[nickw86au]

My sierra (carby) has had problem starting a few times now; it turns over fine (reco starter 2000km ago) and will sort of start but I need to play around with the throttle to get it to start.

It happens after having it running for about 1/2 an hour (or longer; i.e. it is warm), and stopping for about 1/2 to 3/4 an hour.

It seems to be some sort of a fuel problem; today when it happened I actually held the throttle to the floor and turned it over and it finally started.

Clutch starting does not help (I tried) which, combined with the fact that the starter turns it over fine leads me to think it was a fuel problem. I have adjusted the idle down recently, but it hasn't been until a month or two after this that the problem first started occuring.

At first I thought that it might have been flooded, but the fact that I held the throttle to the floor and it started negates this (I think...). I then thought that it could be a vapour lock due to the fact that it happens when the temperature changes; but my fuel cap doesn't seal so well and I tried taking the cap off... no whoosh.

My fuel filter is about 1 or 2 months old; the problem only started occuring in the last 2 weeks.

Could it be my fuel pump or something? How would I know?

THanks for any replies


Nick.

[nicbeer]

Mine does same. Not sure on fix either, i was thinking if it was warm maybe vaporising fuel in float bowl.

Nic

[nickw86au]

So how do you start it? Foot to floor on throttle?

[Potter]

we have a similar problem with our zook. doesnt want to start when its cold. we changed carby with another zook we have, that starts first kick everytime even after we changed carbies. we changed fuel pumps and still the same it starts ok with clutch starting but still doesnt want to run.. as soon as its warm its fine.

[nickw86au]

It starts fine cold - in the morning - if you pump the accelorator to keep the revs around 1200rpm; It's just when it cools down a bit at night and then I go to start it again that this problem occurs.

In regards to your problem I would suggest that you play with the choke. I do this on really cold mornings as my automatic choke doesn't close properly, and I don't even need to pump the accelerator then; it just starts straight away.

[nicbeer]

Yeh, mines only when warm/hot.

Cold starts easily with one pump of acc. When warm/hot and you stop engine have to sit on starter and play with acc to start.

No choke on mine - mechanical but disconnected at moment.

Nic

[nickw86au]

Righto, Thanks for that; I'll let you know if i find a solution.

Nick

[nickw86au]

Still don't have a definative solution, but i've found that if the above problem occurs, I can get it started by holding the throttle flat to the floor and turning it over... I remember reading somewhere that this is the cure for a flooded carb; but I am unsure what holding the throttle flat would do?!?

Anyway, nicbeer see if maybe that helps your situation.

In reading back over the other posts, if

i was thinking if it was warm maybe vaporising fuel in float bowl

is the problem, maybe by holding the throttle flat pumps more fuel into it or something?!?


Nick

[Nev]

mine used to do this too but since i got it rebuilt last year its been starting fine, hot or cold. Id hazard a guess at it being something to do with the choke staying on even when warm...the little corks that control the choke and work off the coolant temp have probably degraded...just a thought from what ive been told of possible problems

[christover1]

Mine did this a lot, now only a little.
Its because when cold choke is working properly, and when hot it works properly, but if parked for only a short time, it cools down but ain't cold...sticky choke was my problem, after rebuild of carby it did improve, but after changing choke mechanism from another carby, it is fixed..

christover

[nickw86au]

Mine did this a lot, now only a little.
Its because when cold choke is working properly, and when hot it works properly, but if parked for only a short time, it cools down but ain't cold...sticky choke was my problem, after rebuild of carby it did improve, but after changing choke mechanism from another carby, it is fixed..

christover

ahh... thanks for that. You obviously stayed with the normal sierra carb when changing to the 1.3 motor?

Nick

[christover1]

Mine did this a lot, now only a little.
Its because when cold choke is working properly, and when hot it works properly, but if parked for only a short time, it cools down but ain't cold...sticky choke was my problem, after rebuild of carby it did improve, but after changing choke mechanism from another carby, it is fixed..

christover

ahh... thanks for that. You obviously stayed with the normal sierra carb when changing to the 1.3 motor?

Nick

yeah, I did look into alternative carbies, but no easy ones suited off road use or my bujet. $40 for a carby kit, and decent filters, fuel pump and a new tank, all problems are gone...sierra 1.3 carbies are great, but only when all is well..they are a p***k when things aint well tho

[nickw86au]

Might be worth putting a carby kit through mine then, and looking into finding another choke assembly. I'll get this cooling system problem (mentioned on another thread) first, tho. 'Spose that the carby kit would probably help preformance a little as well (everything is relative...)

Nick

[christover1]

Might be worth putting a carby kit through mine then, and looking into finding another choke assembly. I'll get this cooling system problem (mentioned on another thread) first, tho. 'Spose that the carby kit would probably help preformance a little as well (everything is relative...)

Nick

coolant issues do affect choke function.....as the auto choke is worked by hot water flow...Its right at the top of cooling system, so if water level drops, choke runs dry and plays up...so yes fix up leaking first, see what happens

christover

[nickw86au]

Good point. Thanks for that christover. I'll get that done this weekend (with a bit of luck on getting required parts) and see how it goes.

Nick.