hif38 carb fitted, just can't get it to run

Discuss mechanical problems here.
Forum rules
By using this site, you agree to our rules. Please see: Terms of Use
Post Reply
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

hif38 carb fitted, just can't get it to run

Post by hanvyj »

Hi,

I've just fitted a hif38, it ran for a few seconds but then stopped. Turns out this was because I'd blocked off the float breather. That's free now but it just won't start. I took a plug out and it was wet with fuel, it has spark... I've tried adjusting the timing. Got to the point where I've just run out of things to try...

Can the mixture be the problem? Should I try leaning out or richening the carb?
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by bmcecosse »

Why would you adjust timing when changing a carb??? If the plugs are wet - you have flooded it me-thinks. Take plugs out and leave overnight..... And pleeeeeeeeeeaaaaaaase - leave the da&% timing alone !!
Last edited by bmcecosse on Wed May 15, 2013 7:27 pm, edited 1 time in total.
ImageImage
Image
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

I think its flooded too, the timing wasn't tightened up properly and I think could have been knocked
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by bmcecosse »

Make sure you are not pumping the fuel into the overflow pipe..........
ImageImage
Image
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

bmcecosse wrote:Make sure you are not pumping the fuel into the overflow pipe..........
Pretty sure I'm not, fuel is going into the lower one, next to the balance pipe (currently blocked off)
horologiumwatches
Minor Fan
Posts: 133
Joined: Sun Feb 08, 2009 11:10 pm
MMOC Member: Yes

Re: hif38 carb fitted, just can't get it to run

Post by horologiumwatches »

bmcecosse wrote:Make sure you are not pumping the fuel into the overflow pipe..........
I've just found this diagram. Should I fit a pipe to the overflow then to exhaust the waste fuel?! I've never known what that second pipe was for and it currently just has a short length of (perished) pipe attached to it. I've never noticed any fuel coming out of it and there is no evidence of such, it is a bit close to the exhaust though so now I'm thinking........ :o
1951 Series MM Lowlight
1954 Series II Four Door De Lux 'The Bomb'
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by bmcecosse »

The overflow must be open - a hose away from hot bits would seem wise...... I'm puzzled about the blocked off 'balance pipe'......Nothing should be blocked.
ImageImage
Image
horologiumwatches
Minor Fan
Posts: 133
Joined: Sun Feb 08, 2009 11:10 pm
MMOC Member: Yes

Re: hif38 carb fitted, just can't get it to run

Post by horologiumwatches »

I think mine is a 44, but they are roughly the same I think.

Image

Sorry to hijack the thread, but it just made me think, and it is sort of relevant.

Tommy
1951 Series MM Lowlight
1954 Series II Four Door De Lux 'The Bomb'
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Yeah just pipe it away from anything hot.

I've got these two blocked off:
Image
Image

Do they have to be connected for it to start?
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

As I understood these were the load weakening 'economy' device
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by bmcecosse »

Surely one is the vacuum connection to the dizzy?
ImageImage
Image
daveyl
Minor Fan
Posts: 255
Joined: Thu Jun 14, 2007 9:10 pm
Location: portsmouth
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by daveyl »

If you do have to strip it, look out for a punctured float.
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Yep, on the bottom right of the top picture goes to the vac advance.
Roni
Minor Fan
Posts: 402
Joined: Wed Jan 04, 2006 2:48 am
Location: Ashburton, NZ
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by Roni »

I have one of these on mine and it runs correctly. It is connected as shown in the first photos except that I have the economy circuit connected. This can be blocked off, as shown, making the carb behave like a normal one.
The vacuum connection for the distributor is next to the dashpot cover.
The float chamber breather is the one next to the crankcase breather connection. I just have a long hose that finishes well away from the exhaust.
Your description sounds like it has flooded.

hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Put the plugs back in, still won't start
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Just got a start by pouring fuel down carb!

Should the choke move the jet up and down? (I'm assuming the jet is the little brass thing the needle goes in)
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Took the bottom off and petrol did not pour out like it did before (when the float wasn't on its hinge)
Last edited by hanvyj on Fri May 17, 2013 12:49 am, edited 1 time in total.
hanvyj
Minor Fan
Posts: 302
Joined: Mon May 30, 2011 10:52 pm
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by hanvyj »

Yep, the float was the problem, took it apart and juggled things, back together and it runs!
bmcecosse
Minor Maniac
Posts: 46561
Joined: Wed Feb 16, 2005 11:24 pm
Location: ML9
MMOC Member: No

Re: hif38 carb fitted, just can't get it to run

Post by bmcecosse »

Well done !
ImageImage
Image
Post Reply