| Author |
 Topic  |
|
|
devnet H120
United Kingdom
81 Posts |
 Posted - 06 Mar 2013 : 22:28:20
|
I think I might be writing this in vain but I have run out of ideas. I have recently done a top end rebuild on my Fastback H120, head stripped, skimmed etc. Carbs rebuilt. It has been put back together in full but for the life of me I cannot get it to start, it turns over and sparks, tries to start almost getting to 1000rpm but no matter how much it turns over it will not take. I think it could be the fuel getting through, as you pump the pedal it is more likely to spark and take but never fully start but the chambers do end up flooding. I have done everything normal the timing is spot on, fuel is getting to the carbs, jets have been cleaned, good pressure in chambers etc.
Not sure if anyone has an idea but any help would be appreciated.
Thanks in advance.
devnet H120 |
|
|
JPSH120
United Kingdom
1183 Posts |
Posted - 07 Mar 2013 : 07:13:43
|
They can be a bit of a swine to start at times! Are you using choke and what airbox set up have you got for the carbs?
___________________________________________________________________________
 |
 |
|
|
devnet H120
United Kingdom
81 Posts |
Posted - 07 Mar 2013 : 14:12:38
|
Yes it is becoming frustrating. I only use the choke when the engine almost starts to take and it does help sometimes but I mainly use the pedal to pump the fuel in which helps to catch it. The air box set up is the original red box to grey twin pipe inlet box.
I think it might be the fuel getting down the inlets but its getting in there when pumped but not otherwise I think..?!
Cheers.
devnet H120 |
|
|
|
JPSH120
United Kingdom
1183 Posts |
Posted - 07 Mar 2013 : 15:37:02
|
I never used my choke, it was a waste of time! Are the carbs balanced? I know they are temperamental little buggers!
A method that was always fairly successful for me was a couple of pumps on the throttle and then hold it down slightly when cranking, as it catches then pump gently.
Also, do you know the fuel pump is working correctly?
___________________________________________________________________________
|
|
|
|
arrocuda
United Kingdom
501 Posts |
Posted - 07 Mar 2013 : 17:00:14
|
One thing that happened to me a few years back that produced similar symptoms was when I had rebuilt some twin carbs and overhauled a cylinder head. Turned out I had forgotten to tighten up the connections on the linkage rods that work the throttle and chokes on both carbs. Took me a couple of hours to figure out what was happening, I was so convinced it was the timing that was wrong.
Building the 'Mark II' fastback Rapier ('Arrocuda'). |
|
|
|
1922
United Kingdom
549 Posts |
Posted - 07 Mar 2013 : 20:51:38
|
Starting procedure for mine when cold was full choke and two pumps on the throttle - used to start in less than one turn. Then back off the choke pretty quick - 30 seconds or so.
Apologies if this is a silly question - are you sure you've got the plug leads in the correct order (1342 anti-clockwise on the distributor).
By "good pressure in chambers" do you mean cylinder compression?
If not - are the valve clearances too tight? This one caught me out once, clearances too tight and the valves didn't close properly and it wouldn't run.
 |
|
|
|
bigt80
United Kingdom
1052 Posts |
Posted - 08 Mar 2013 : 08:58:31
|
Have you tried using Bredex or similar easy-start? If it fires on this then your problem is pretty likely fuel. I was just saying to JPSH120 that my long time off road car had been fired up OK and then next day did not want to know: turned out to be a collapsed fuel hose between pump and carb that was not allowing sufficient fuel through. That's on a std F'back though.
Incidentally: starting technique for my H120 was two or three prods on throttle and then a little giggling of throttle and away. Chokes removed years ago. The little owners' manual supplement you got with the car on the H120 says full choke for a cold start! Who were they kidding.
Sorry, I digress, but re your start problem I think you need to determine if it is fuel or electrics. 1922's suggestion isn't so daft. I mucked my Audi up because it is clock-wise rotation and I based the rotation as being same a Rapier! D'oh. |
|
|
|
grumpy1
United Kingdom
34 Posts |
Posted - 09 Mar 2013 : 16:14:46
|
| Not my usual thing to advise anyone on mechanical probs...there are many much more knowledgable than me. However, I had my Stag off the road since before Christmas, with carb and fuel pump issues due to extreme cold weather between then and now. When I got it all back together, I tried my usual amount of choke (1/4 - 1/2 inch). Nothing. Fuel was getting through OK, but just not firing. Cheched plugs for spark (all 8!) Fine. Then, after 20 minutes of frustration, I did something I've never had to do in 12 years of ownership. I pulled to choke right out...fired first turn! Once warmed up and used, it is back to the usual amount of choke from cold. Try it. you may be surprised...or not! |
|
|
|
Rootes 66
United Kingdom
4 Posts |
Posted - 10 Mar 2013 : 08:06:09
|
Try some fresh fuel, modern fuels will deteriorate if sat in the tank over winter, another option if you are confident with your work is to tow start it, have done it a number of times on newly built engines.
Good Luck |
|
|
| |
Topic |
|
Engine Trouble
