Leaking gas from rear carb & other issues...

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Regarding my project '76 Java Green FHC (4-speed with Z-S Carbs & dual choke cables)...

When I can get it started, it seems to idle where it's suppose to (little under 1K RPMs), but I'm leaking fuel from the rear carb. Using a mirror, it appears to be coming from the choke/cable area (fast idle screw & cam). Not much, just drops. But still a leak. Any ideas? All fuel lines have been replaced with new ones - no leaks from there.

Also - when the car is idling fine, if I rev it up to above 2K - or try to drive it, it sputters and wants to die. Almost like it gasping for fuel or air. I installed a new fuel filter and even ran gas from a 5 gallon can bypassing the gas tank (thinking the issue was rust from the tank). No difference. Same thing.

And occasionally when the car is idling, doing well, it will just instantly die - like someone shut it down. Afterwards, I'll restart it and it will idle just fine.

Ideas? Not sure if any or all are related, but figure I get the gas leak resolved first...

thanks everyone!

Chris
'76 Java Green FHC – a continued work in progress

[Hasbeen]

Hi Chris, I don't know enough about Strombergs to be able to advise much.

Mildred does. Have you read the 3 items in our new workshop section on them, that she has posted. I think that might be your first stop in diagnosing your problem.

I'd be checking the float bowls for silt, & the needle & seat in that back carb particularly, for wear or foreign bodies causing problems, & a tutorial in just this job is there.

Don't be surprised if you have 2 different problems causing your problems. I'd be checking fuel pressure looking for that stall problem.

One poor mans check for pressure is to run the engine for a period, turn it off, wait 30 seconds or so, & then remove the fuel hose from one carb, [doesn't matter which one]. A small squirt of fuel should come from the hose as you remove it, from residual pump pressure. If not have a pump problem, or a leaking needle & seat in a float bowl.

Hasbeen

[Workshop Help]

Our first guess based on our own little carburetor battles is the inlet float valve has worn out. A second guess is the float is leaking, or has become too heavy from accumulations of gasoline deposits, or the float level is too high.

In any event, we cordially invite you to view our Workshop Manual with attention directed at the article on Z-S float bowl removal and inlet valve replacement. Not all that long ago we replaced ours with the aftermarket inlet valves called 'Gross Jets'. They are functioning as advertised with no problems. It is also important to set the floats at the prescribed level after ascertaining no leakage is present.

It is further recommended the float bowls be cleaned and no residue of old silicone sealant be present from prior attempts to seal the drain plug o-ring. Silicone sealants degrade in modern alcohol laced fuel causing globs of the sealant to be sucked up the metering needle where it becomes stuck at the jet. This so leans the mixture the two affected cylinders are fuel starved. If any silicone sealant must be used, apply it only on the outside of the drain plug O-ring to prevent it entering the float bowl.

After cleaning the float bowl, lightly grind the flange flat on a sheet of emery paper mounted on a sheet of glass. This will eliminate any warpage on the bowl flange to effect a tight joint seal.

Mildred Hargis

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Thanks for the replies Hasbeen and Mildred.

Yes - I have been following all of Mildred & others How-Tos in the workshop section - and was thinking about the carbs float bowls as well. Was also thinking about the fuel pump (for the stall issue issue and the sputtering).

I'll look into the float bowls and check the pressure and report my findings.

Thanks!

BTW - Hasbeen, I really enjoy your blog. Thanks for sharing your stories!
Mildred - thanks for sharing your tips in the workshop!

Chris
'76 Java Green FHC – a continued work in progress

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So I removed the carb bowls last night...

Look what I found...[:0]

Here's some before/after pics of one of them (both were in the same condition). What do you think?

Before:






After:




I did confirm that the drains are not leaking (filled them up with vinegar and let them sit for awhile - no leaks)

Still need to reassemble and test.

Chris
'76 Java Green FHC – a continued work in progress

[Hasbeen]

Wow, that is much more than a little silt. You've had a fair bit of water in there. I'm surprised it was going.

Do you have an in line fuel filter, change if you have, & fit one if you don't.

Your fuel pump is probably similar, & should be cleaned too. Take the top off to see what it's like, & clean the strainer.

I'd also try to get any water out of the tank.

Glad you like the racing tails.

Hasbeen

[Workshop Help]

I suspect your floats are caked over as well. will you be pulling the inlet needle valves as well? Now is a good time to replace them considering their age and contamination from old gasoline deposits.

Folks, these photos prove my prior admonitions that our cars need to be used as regular transportation to prevent these kinds of deposits from forming.

Mildred Hargis

[Beans]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Mildred</i>

... our cars need to be used as regular transportation to prevent these kinds of deposits ... <hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">
I am the last to disagree with that [:D]

<center>
<font color="blue"><i>1976 TR7 FHC (needs some TLC ...)
1980 TR7 DHC (my first car, a.k.a. Kermette)
1981 TR7 FHC (Sprint engined a.k.a. 't Kreng
</font id="blue"><b>[url="http://www.tr7beans.blogspot.com/"]<u><b><font size="3"><font color="red">My full Blog</font id="red"></font id="size3"></b></u>[/url]</b></i></center>

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For now, I'll be cleaning everything real good - bowls, floats, etc.

Yes - I put on a new fuel filter (as well as all new fuel hoses and cleaned out the metal lines). I also ran a hose from a 5-gallon gas can to the engine (with new filter), eliminating the gas tank. Still had issues - but that was with the dirty bowls and stuff as shown in above pics. Once I get everything cleaned, check the fuel pump strainer and put on another fuel filter (cheap and easily obtainable), I'll try my test again using the gas can.

Chris
'76 Java Green FHC – a continued work in progress

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Well had some success last night working on the 7.

After cleaning the bowls, floats, etc.. and check and cleaned the fuel pump strainer (wasn't bad at all), I put everything back together and had my lovely assistant (aka: wife) start it up as I examined for leaks (with fire extinguisher at had). Once started and at idle, I was happy to report no more leaks from the carbs. I did notice an ever-so-slight dribble from the nut on top of the fuel pump. I'll have to address that.

While resolving the carb leaks, the engine still didn't want to rev at all. As my wife says, it feels "hollow" when she stepped on the gas. The longer I let the car idle, the worse it got, where eventually it would die and not want to start.

As I was about to call it a day, there was one thing that I had been putting off since day one: check the spark plugs. (I put it off because the PO said he had put new plugs in). So as I pulled them out, I found two interesting things. First, they were wet and smelled of fuel. Second, the gap was set to around .040 - where the manual states it should be .024-.026. (car has the stock ignition) Never saw a gap so small before!

So I wipped the plugs dry, reset the gap, and had my assistant start the car. WOW. [:D] The car sounded the best I had ever heard it since our ownership. Not only did it roar to life at the first twist of the key, but whereas before the engine would attempt to die when reved, now it revs easy and with some authority! Sounds good too!

The more we kept reving it and listening to the note, I noticed the spunk was slowing fading - probably due to the plugs getting fouled with fuel again.

This world of carburetors is all-new to me (but am enjoying learning!). I take it it's running too rich causing fuel to foul up the plugs and hinder performance? Earlier test with the carbs showed that if, at idle, I slightly raise the piston in the rear carb, the engine would die, whereas doing the same test to the front carb it wouldn't. Also, a lot more hissing from the rear carb. I plan to follow the steps in Mildreds "The Zenith-Stromberg Saga" over the weekend.

Also plan to install a fuel pressure gauge to monitor it.

Am I on the right track?

Chris
'76 Java Green FHC – a continued work in progress

[Hasbeen]

You'll be writing items for the workshop section any time now.

Hasbeen

[Workshop Help]

Yes, you're on the right track, just don't let the train run you over.

Okay, have you installed a set of new spark plug cables and did you test them to confirm none are defective? Please refer to my article on spark plug cables in The Workshop Manual.

Next, did you replace the carburetor inlet valves to prevent flooding? This needs to be done before fiddling with the carburetor settings along with the float level, which should be 5/8".

Once these two basic items are done, you will then be ready for the gruesome act of Z-S tuning.

As always, your personal pit crew stands poised for immediate response.

Mildred Hargis

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Hasbeen - thanks. I like to write. [:D] But gonna leave the Workshop to the pros like you, Mildred, FI Spyder, Jclay, Beans, HDRider, Peter, and all the others !

Mildred - Yes - plugs, wires cap & rotor are all new (by PO back in Nov '13). Have receipts for them from VB. All look new and in good shape. Just the gap was incorrectly set. No problem testing the wires.

No - I didn't replace the carburetor inlet valves. Where can I get them? Are they included in the Z-S Carb rebuild kit? What all is involved with replacing them (besides removing the bowl)?

Chris
'76 Java Green FHC – a continued work in progress

[Hasbeen]

You should get them from the usual Triumph TR7 suppliers, & they should be in any rebuild kit.

If you are having trouble, the needle & seat are interchangeable between the 1 3/4 SU & the Zenith. I assume that means they should be available from Jag suppliers too.

Save the washer under the old ones. You sometimes need to use 2 or 3 washers under the seat, to lower the float level a little.

Hasbeen

[Workshop Help]

The inlet valves themselves are found in the rebuild kit as may be viewed in your V-B catalog. However, for considerable less cost, the aftermarket 'Gross Jets' are also available from the same source, as I recall.

The inlet valve is located on the underside of the carburetor body. Once the float is removed, access is easy. Be sure, using a 6" ruler, to reset the float level at about 5/8" following the directions in the factory workshop manual.

Mildred Hargis