TRExp

Spitfire & GT6 Forum

Don't light a match around this engine.... Phew!!

Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

jleclainche Jacques Le Clainche
Elbert, CO, USA   USA
I ran my Spitfire with its downdraft Weber carb for two years without problems, till the mechanical fuel pump started leaking like a sieve. Instead of rebuilding or buying a new mechanical pump, I fitted a cheap Mr. Gasket #42 electric pump. Fuel pressure is from 2 psi to 3.5 psi, so no need for a fuel pressure regulator. I set it up so I can change the pump in less than 10 minutes on the road. I have had that pump on the car for over three years, and it has not failed yet.

I also have a better (but bigger) pump: Airtex E8016S, fuel pressure from 2.5 psi up to 4 psi. As the max (4 psi) is over what the Weber is designed for, I also got a Mr. Gasket fuel regulator. You can adjust the fuel pressure from .5 psi up to 5.5 psi. In the end I did not use it as the Mr. Gasket pump #42 was a smaller and simpler set up.

Somebody on this forum just did me a favor, so I am paying it forward: if you want the Airtex pump and/or the fuel regulator, you can have that for the price of shipping.



Edited 2 time(s). Last edit at 2018-02-02 10:21 AM by jleclainche.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
Even a Mr Gasket dialed to low works.





Edited 1 time(s). Last edit at 2018-02-02 11:20 AM by Doug in Vegas.

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
I've got to agree with Carter...... original set-up from PO... included Weber 32/36 downdraft modification. Standard and typical set up.... fuel pressure was never an issue....

So - I rebuilt the weber - and somehow missed a float needle assembly washer... and was flooding the carb (big time).... put the float needle washer in properly (there were actually two of them somehow).... and got her running "kinda sorta properly"..... (adjusted float also (35mm closed with no pressure on spring loaded ball - 51mm full open))...

This morning (17 degrees) - I finally got her to fire....(thanks to ether)... and started trying to tune it up..... No overflow (thanks Dan)..... though there were a couple of explosions under the hood before the richness went away... LOL

Once the smoke cleared (mostly due to bolt penetrator liquid on the exhaust system).... I started trying to tune her....

Can't get her below 1600 rpm..... (unless I push down hard on the throttle assembly.... Idle adjustment screw not contacting linkage. Idle needle valve is completely closed..... opening it up - causes stumbling......

I think she's running way to rich due to primary...

Jets are: 170 primary - 160 secondary.... (came with car).....

I'm guessing - I might want to reduce the primary jet at this point..... to attempt to get a smoother/lower/appropriate idle where the idle mixture screw has the proper effect..... (1.5 - 2 turns out).....

For more information.... the timing was set prior to the rebuild (12degrees BTDC because 10 degrees wouldn't work properly) - and I have not adjusted it since the rebuild of the carb.... Maybe I should before replacing jets....

I'm a firm believer that forum info is just as good, if not better, than factory spec sheets..... These cars are old.... lots have been done to them.... and personal experience (IMHO) takes precedence.....

Thx all.....

Z

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
Let her sit for a few hours with the charger on her...... in 27 degree weather (inside the garage... 14 outside) ..... then went back to the garage to check her out....

Sweet little thing fired up on the first crank.... but still idles (no choke engaged) at 1600 - 1800..... Can't reduce it without pushing "hard" on the throttle linkage....even that doesn't do much...

Let her warm up.... shut her down for 5 minutes.... and tried again..... Fired up on first crank.....

That's encouraging.... Now to figure out why she's idling so high....

Z

carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
Check your manifolds to head mating surfaces. Try to slip a piece of paper in behind the intake manifold.



'S all for now
Vic

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
That ain't going to happen... LOL.... PO left a manifold bolt/nut off.... which I'm sure was a part of my original crappy idle/running condition..... Ordered the proper part to tighten it down - and torqued all manifold bolts.... I do have a brand new fel pro gasket on my desk - but am waiting to replace the stock exhaust prior to putting it on....

Even so..... If I had a manifold leak... I'd be running lean at idle.... With my mixture screw closed entirely - I'm idling at 1700.... smooth as silk - but can't get her lower... If I open up the mixture screw - my idle goes to crap. sounds rich to me..

I'm going to check linkage/butterflies in the morning to make sure she is closing as far as proper.... as I mentioned - if I push hard on the throttle I can get it to drop a couple of hundred rpm until I let up on the pressure.... I might have some sort of unintentional bind since the re-install - but I don't think so....

After that, unless I get a better idea - I'll experiment with smaller primary idle jets...... Mine are Redline conversion stock.... but might be to big.... I Just Don't Know....

but I love that she fires up quickly.... the whole reason behind the rebuild was overly rich mixture - making starting difficult - especially when warm...

Thx,

Z

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
In reply to # 1511011 by jleclainche I ran my Spitfire with its downdraft Weber carb for two years without problems, till the mechanical fuel pump started leaking like a sieve. Instead of rebuilding or buying a new mechanical pump, I fitted a cheap Mr. Gasket #42 electric pump. Fuel pressure is from 2 psi to 3.5 psi, so no need for a fuel pressure regulator. I set it up so I can change the pump in less than 10 minutes on the road. I have had that pump on the car for over three years, and it has not failed yet.

I also have a better (but bigger) pump: Airtex E8016S, fuel pressure from 2.5 psi up to 4 psi. As the max (4 psi) is over what the Weber is designed for, I also got a Mr. Gasket fuel regulator. You can adjust the fuel pressure from .5 psi up to 5.5 psi. In the end I did not use it as the Mr. Gasket pump #42 was a smaller and simpler set up.

Somebody on this forum just did me a favor, so I am paying it forward: if you want the Airtex pump and/or the fuel regulator, you can have that for the price of shipping.

Thanks for the offer Jacque... I'll take you up on it......

While I don't think fuel pressure is an issue right now.... I also think that eliminating all potential problems is nothing but wise...... At some point - my mechanical pump will crap out and I'll want to change to electric... why not do it now..... along with the regulator....

I'm a big believer in "paying forward".... and maybe your offer is my reward for something I did in the past for another unfortunate....

PM me if you're serious - with details....

Thx,

Z

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
jleclainche Jacques Le Clainche
Elbert, CO, USA   USA
PM me your street address, and I'll mail you both the pump and the regulator either tomorrow afternoon or Monday morning. When you receive the package, just mail me a check for the amount of postage shown on the package. My address will be on the the package.

spitfire50 Avatar
spitfire50 Paul Mugford
Rochester, N.H., USA   USA
Steven,
I have to vote with Victor on this. An engine can't run faster because it gets a richer mixture. It has to get more air to run faster. The fact that forcing the throttle shut beyond its rest position slows the engine shows that extra air is getting in somehow. You can try spraying water from a pump spray bottle at things to find the leak, or you can add fuel by either spraying carb cleaner around or wave an unlit propane torch at any suspect spots. Water will cause a stumble. Fuel usually causes a rise in revs.
All the best,
Paul

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
I will take the advice later this morning (when it warms up to 20)....

thx to both...

Z

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
Just got back from the garage...... I sprayed enough water around the carb/manifold to float a small boat.... No change....

Then studied the linkage some more.... " Something" is keeping the butterflies just slightly open....(appear closed from the topside, but slightly open from the bottom side... so I pulled the carb - and am going through it with a fine tooth comb (and a Budweiser).... I'm going to bet there is something going on between the carb linkage and the choke linkage....

(edit).... secondary butterfly stop was just barely high enough to keep secondary open at idle (just barely)... so I backed it off a half turn..... choke fast idle adjustment screw was keeping primary open a pretty good amount (results of messing with choke prior to rebuild)... so I backed it off also to allow primary butterfly to close......

I'll go back and try again later (once my fingers thaw out).... unless someone suggests anything different....

Z



Edited 1 time(s). Last edit at 2018-02-03 10:02 AM by TheZster.

TheZster Avatar
TheZster Steven Z
SAINT LOUIS, MO, USA   USA
Eureka!!! Success - for now!!

It ended up being pretty simple (what else is new?).... Choke fast idle screw was keeping the rpm's way to high by keeping the primary butterfly open a tad..... I thought the screw was clear of the cam - but my shop light died a couple of days ago - and my eyesight is not that great. While investigating, I lowered the secondary butterfly stop just a tad to keep that one closed at idle....

I've got her idling at 850/900 rpm.... smooth as is possible for this girl (don't try to tell me you can't tell if it's running without looking at the tach - I don't believe it).... But no shimmy/shake on the engine.....

idle mixture screw out 1.5 - 2 turns..... idle stop down way low... Just like the book says (imagine that!!)

Ran her up to temp... then shut her down multiple times - with up to 10 minutes between starts (simulating my typical no start scenario of stopping for a coke or fuel)....... Fired right up.... I wonder though.... you can't tell if it started when cranking her.... but when you let up on the key - there it is... running smooth... I'll find out in the morning after she sits overnight whether it's really cured.

THANKS to all for your feedback..... Some ideas may not have cured the problem - but surely eliminated other possibilities once I did testing.


Z

carChips Avatar
carChips Victor Harnish
Kelowna, BC, Canada   CAN
1933 MG Magnette
1973 Triumph Spitfire 1500 "Chip"
1989 GMC Sierra 1500 "Bush Truck"
Miller time! smileys with beer



'S all for now
Vic

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, NV, USA   USA
Fantastic! Let it cool off and press once on the throttle to see if the step cam snaps back thus increasing the idle again. The trick is to get it to do that on target as the engine warms up.

jleclainche Jacques Le Clainche
Elbert, CO, USA   USA
Package was sent yesterday. Please check PM.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions




Registration is FREE and takes less than a minute!


Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster





Join The Club

Sign in to ask questions, share photos, and access all website features

Your Cars

1965 Triumph Spitfire MkII

Text Size

Larger Smaller
Reset Save

Sponsor Links