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running issue
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Jason



Joined: 12 Nov 2008
Posts: 623
Location: Todmorden, Lancs.

PostPosted: Sat Sep 29, 2012 10:51 am    Post subject: running issue Reply with quote

I took the Alvis out for a run the other day and its running perfect with plenty of power.
I got on an open bit of road and gave her some 'beans' and when I got above 45mph, the engine tried to die.... then if I drop below 45mph its fine again.

there's no backfiring and has loads of power at slow speeds.

I'm guessing its fuel starvation at high revs and hoping its something simple like a blocked jet in the carb, but could do with a second opinion before I start stripping the carb down.

thanks in advance
jason
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Penman



Joined: 23 Nov 2007
Posts: 4750
Location: Swindon, Wilts.

PostPosted: Sat Sep 29, 2012 11:36 am    Post subject: Reply with quote

Hi
Does it do the same thing in lower gears at the same revs?

Older cars wouldn't have electronics that changed settings relative to gear so the symptoms should show relative to revs.
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Jason



Joined: 12 Nov 2008
Posts: 623
Location: Todmorden, Lancs.

PostPosted: Sat Sep 29, 2012 11:41 am    Post subject: Reply with quote

mmmm.....not tried that mate, I'll fire her up and check.

cheers
jason
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welshrover



Joined: 09 Aug 2011
Posts: 326

PostPosted: Sat Sep 29, 2012 4:27 pm    Post subject: Reply with quote

i had a similar problem with my wifes hillman. the main jet in the carb was partially blocked .it was ok slow, then up the revs and it would start to struggle like you said .but only under load, when it was revved at idle it didnt show as a problem .
probably just needs a shilling tune up. Very Happy Very Happy
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47p2



Joined: 24 Nov 2007
Posts: 2009
Location: Glasgow

PostPosted: Sat Sep 29, 2012 5:08 pm    Post subject: Reply with quote

Sounds like a fuel issue, what make of carb is on the car?
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Jason



Joined: 12 Nov 2008
Posts: 623
Location: Todmorden, Lancs.

PostPosted: Sat Sep 29, 2012 9:14 pm    Post subject: Reply with quote

I've had her running this afternoon and she does seem to die if given a lot of throttle (high revs).

I think I'll strip the carb tomorrow and give it a good clean out.

it's an SU H4 carb and to be honest, I've not touched it since rebuilding it about 4 years since.....so probably just needs a clean out.

I'll report back tomorrow after I've had a play Wink

jason
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MVPeters



Joined: 28 Aug 2008
Posts: 822
Location: Northern MA, USA

PostPosted: Sat Sep 29, 2012 10:47 pm    Post subject: Reply with quote

Using the rule "Do the easy bits first", I'd check the fuel filter &/or pump.
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Penman



Joined: 23 Nov 2007
Posts: 4750
Location: Swindon, Wilts.

PostPosted: Sat Sep 29, 2012 11:23 pm    Post subject: Reply with quote

Hi
Don't forget it is also possible for the spark to break down under load.
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Bristols should always come in pairs.

Any 2 from:-
Straight 6
V8 V10
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Jason



Joined: 12 Nov 2008
Posts: 623
Location: Todmorden, Lancs.

PostPosted: Sun Sep 30, 2012 3:53 pm    Post subject: Reply with quote

this morning I cleaned out the glass bowl filter and the small brass filter in the fuel pump, there was no visible dirt in either but the car seems fine now.

I've done about 5 miles this afternoon and she run perfect, so I've no idea what it was. Confused
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trampintransit



Joined: 09 Aug 2010
Posts: 166
Location: Edinburgh

PostPosted: Tue Dec 11, 2012 7:01 pm    Post subject: Reply with quote

Brilliant....that's the kind of fix we like~ Very Happy
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