prawnabie
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| posted on 21/1/09 at 01:14 PM |
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Xflow running problems
Hi guys
I have just finished rebuilding my locost. The engine is a 1700 xflow.
When starting from cold, the engine will misfire through the carbs a few times until it is warm. Also, when the engine is up to temp, it is a right
pain to start again. The engine turns over and it tries to fire, eventually it will catch. It starts normally when cold though. Could it be the timing
out. Engine drives fine though.
Timing is set at 12 BTDC
Engine specs are
kent 234 cam
1300 pistons in 1700 block.
Rally spec bestek elec igniton
twin 40 dcoes
Thanks
Shaun
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Mr Whippy
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| posted on 21/1/09 at 01:26 PM |
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Don't bother about the spitting when cold, many over carbed engines do that easpecially if you are using after market air filters. It might be a
bit lean though which could be causing the hot poor starting. Have a look at the spark plugs after a run to see if they are glazed or very cleen which
might indicate the engines too hot and lean
[Edited on 21/1/09 by Mr Whippy]
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yellow melos
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| posted on 21/1/09 at 01:51 PM |
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Has this just started to happen or has it always been like that ???
possible valve or valve seat problem ????
or maybe the springs are not good enough for the cam you have....
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britishtrident
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| posted on 21/1/09 at 02:04 PM |
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What are your cCarb jets sizes, choke sizes & emulsion tubes ?
How is the ignition triggered ie from the distrubuter ?
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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02GF74
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| posted on 21/1/09 at 02:58 PM |
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you don't mention having a choke? whe it is cold, it is almost essential to require the use of one although it is closed off failry quickly; in
hot weather no choke is needed.
you know about the magical starting sequence?
depress the accelerator 4 or 5 times so the pumps squirt a bit of petrol in then turn the igniton key?
re: Also, when the engine is up to temp, it is a right pain to start again.
this is a bit strange - which does show there is something amiss.
this 12 deg timing - where did you get that value from?
how did you set the timing? are you sure the timing mark on pulley and timing chain cover TDC is correct?
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britishtrident
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| posted on 21/1/09 at 03:08 PM |
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quote:
Originally posted by 02GF74
you don't mention having a choke? whe it is cold, it is almost essential to require the use of one although it is closed off failry quickly; in
hot weather no choke is needed.
you know about the magical starting sequence?
depress the accelerator 4 or 5 times so the pumps squirt a bit of petrol in then turn the igniton key?
re: Also, when the engine is up to temp, it is a right pain to start again.
this is a bit strange - which does show there is something amiss.
this 12 deg timing - where did you get that value from?
how did you set the timing? are you sure the timing mark on pulley and timing chain cover TDC is correct?
ISTR it was not unknown for the litle brass pistons in the cold start enrichment valve of DCOE carb to stick. Easy enough to check -- take of the
top lids of the carbs and you should seen them move when the choke lever is operated. If they are stuck remove the two screws that hold the choke
lever mechanism on and use a smaller tapered tap to catch hold of the little brass pistons and pull them out.
[Edited on 21/1/09 by britishtrident]
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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prawnabie
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| posted on 21/1/09 at 08:23 PM |
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Hi
Thanks for the replies.
I have set the timing to 12 btdc as a rough guide to get the engine running. The engine is pretty much brand new.
The webers have no choke control fitted (cable etc) and were jetted for a 1600 + 60 crossflow by vulcan, so I hoped they would be alright to get it
running.
The camshaft was fitted as a kit with kent double valve springs.
The engine starts ok in the colld with a few presses of the pedal before hand, and when up to temp it runs pretty well.
Its just that after a 5 minute run, it really struggles to start.
what to you reckon the timing should be roughly set to on an engine in that state of tune?
Thanks
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