Hey - did you know if you click on the title of a thread it will take you to the first unread post since you last visited that thread?
but were afraid to ask: 
STOP!! Never post your email address in open forums. Bots can "harvest" your email! If you must share your email use a Private Message or use the 
smilie in place of the real @
Pretty Please - add it to our Events forum(s) and add to the calendar! >> 
Finally getting back on my 1960 TR3. Sold the other. At one point in time had 2 cars running on 4 cylinders between them. My 60 starts with the choke full on. When I try to idle it down it runs really ragged. Pulled the 2 front plug wires off and no difference. I can spray gasoline into the front carb and the engine smooths out until the gas is burned. Carbs freshly rebuilt, float bowel full. Linkage hooked up and free? any ideas? Randall you were right about my generator. It was bad, not the control box. the brushes were stuck in their holders.
-
Hey Guest!
British Car Forum has been supporting enthusiasts for over 25 years by providing a great place to share our love for British cars. You can support our efforts by upgrading your membership for less than the dues of most car clubs. There are some perks with a member upgrade!**Upgrade Now**
(PS: Upgraded members don't see this banner, nor will you see the Google ads that appear on the site.)
TR2/3/3A TR3 Misfire +[ Randall you're correct again]
- Thread starter oxendine
- Start date
Share this page
TR3driver
Great Pumpkin - R.I.P
Offline
I'd pull the float bowl off and pour out whatever is in it. Check that the passages are clear, then reinstall the bowl & fill with fresh fuel (preferably from a can rather than from the pump). If that doesn't work, remove the jet (without disassembling the carb, so you don't upset the centering, etc) and check that it is clear.
The E10 they sell these days seems to dry to a hard rock-like substance that even "carb cleaner" will not dissolve. So it could be that the fuel in the jet has dried and the deposit clogged the jet. I had to literally chip it out of the main jet on my lawnmower!
Or the fuel may have gotten damp enough to get "phase separation" and there is water in the bowl/passages. Or the gas is just so old it won't burn.
Hmm, I'm assuming you are letting the engine warm up before trying to run it without the choke on. I have to drive several miles before mine will idle without having the choke out at least a bit, and it's probably warmer here than in Huntingburg.
The E10 they sell these days seems to dry to a hard rock-like substance that even "carb cleaner" will not dissolve. So it could be that the fuel in the jet has dried and the deposit clogged the jet. I had to literally chip it out of the main jet on my lawnmower!
Or the fuel may have gotten damp enough to get "phase separation" and there is water in the bowl/passages. Or the gas is just so old it won't burn.
Hmm, I'm assuming you are letting the engine warm up before trying to run it without the choke on. I have to drive several miles before mine will idle without having the choke out at least a bit, and it's probably warmer here than in Huntingburg.
Re: TR3 Misfire
I removed what I felt comfortable with and sprayed carb cleaner down the jet. When I did that there was no obstruction between it and the float chamber as what little fuel remained there splashed out. I put things back together again and had the same thing, cylinders firing when I spray fuel into the throat and not firing when the fuel runs out. Got plenty of fuel pressure rear setup works fine, it's just the front that has me stumped.
I removed what I felt comfortable with and sprayed carb cleaner down the jet. When I did that there was no obstruction between it and the float chamber as what little fuel remained there splashed out. I put things back together again and had the same thing, cylinders firing when I spray fuel into the throat and not firing when the fuel runs out. Got plenty of fuel pressure rear setup works fine, it's just the front that has me stumped.
trrdster2000
Luke Skywalker
Offline
Re: TR3 Misfire
Does the piston go up and down freely or if you push the piston up slightly will it draw gas and smooth out. I have seen stuck pistons cause this with two different problems, (1) the screws on the piston crown were screwed all the way up tight one at a time and it locks the piston by cocking the crown one way or the other and (2) the needle not being centered in the jet, see if it clicks when being dropped from about halfway up.
Wayne
Does the piston go up and down freely or if you push the piston up slightly will it draw gas and smooth out. I have seen stuck pistons cause this with two different problems, (1) the screws on the piston crown were screwed all the way up tight one at a time and it locks the piston by cocking the crown one way or the other and (2) the needle not being centered in the jet, see if it clicks when being dropped from about halfway up.
Wayne
trrdster2000
Luke Skywalker
Offline
Re: TR3 Misfire
Thinking about your problem overnight and it was painful, not a lot of activity up there.
Get a half sheet of paper and stick it over the carb to see if it sucks it in, if not you have a major air leak somewhere or just use the unisyn and see if the ball goes up and down. If so, we have ways to find it.
Wayne
Thinking about your problem overnight and it was painful, not a lot of activity up there.
Get a half sheet of paper and stick it over the carb to see if it sucks it in, if not you have a major air leak somewhere or just use the unisyn and see if the ball goes up and down. If so, we have ways to find it.
Wayne
Re: TR3 Misfire
Today I started over again by going step by step with the SU manual. Adjusted the jets and linkage and so on. For some reason the front carb is where the problem is. I seem to have more vacuum from it than the rear? When the choke is full on it seems to run okay. It might seem that way because the engine is running pretty fast and a miss is not so noticeable. A friend of mine is coming over this week to see what he thinks. I'm missing some great driving weather here. Winter to arrive in a few weeks. Still got the Morris Minor to to keep me from going nuts.
Today I started over again by going step by step with the SU manual. Adjusted the jets and linkage and so on. For some reason the front carb is where the problem is. I seem to have more vacuum from it than the rear? When the choke is full on it seems to run okay. It might seem that way because the engine is running pretty fast and a miss is not so noticeable. A friend of mine is coming over this week to see what he thinks. I'm missing some great driving weather here. Winter to arrive in a few weeks. Still got the Morris Minor to to keep me from going nuts.
poolboy
Yoda
Offline
Re: TR3 Misfire
I had a TR6 engine running similar to that. I spent a couple days fooling with carbs even chaning to a spare pair that I had just refurbished for a friend.
Really started getting to me because I fancied that I knew ZS carbs pretty well.
In the end, I swaped distributors from my car to this engine and the engine straightened out. So let me say this before someone else does and claims it's his saying, which it's not (I don't think any of us have been around long enough to claim it as "his").
"90% of carb problems are electrical"
I had a TR6 engine running similar to that. I spent a couple days fooling with carbs even chaning to a spare pair that I had just refurbished for a friend.
Really started getting to me because I fancied that I knew ZS carbs pretty well.
In the end, I swaped distributors from my car to this engine and the engine straightened out. So let me say this before someone else does and claims it's his saying, which it's not (I don't think any of us have been around long enough to claim it as "his").
"90% of carb problems are electrical"
racingenglishcars
Darth Vader
Offline
Re: TR3 Misfire
A large vacuum leak, like where the carb bolts on to the manifold could cause misfiring at idle on only two cylinders.
A large vacuum leak, like where the carb bolts on to the manifold could cause misfiring at idle on only two cylinders.
Bremer
Jedi Hopeful
Offline
Re: TR3 Misfire
I had a similar problem recently, see link:
https://www.britishcarforum.com/bcforum/u...ders#Post786612
I had a similar problem recently, see link:
https://www.britishcarforum.com/bcforum/u...ders#Post786612
Bremer
Jedi Hopeful
Offline
Re: TR3 Misfire
Well, as I had described in my original thread, the carbs were grossly out of synch, giving the impression that the engine was running on two cylinders only. I removed the rear carb (which was drawing more air than the front one) and realigned the throttle plate a bit. It was a subtle change, but it improved things significantly and allowed decent synchronization. Both throttle bores are somewhat worn (tips on how to fix that are welcomed), so idle speed isn't quite as low as I would like it but it's acceptable for now.
Bottom line: It never ran on only two cylinders, but the symptoms were such that I thought it did.
Hope this might help the original poster scratch another item off the list...
Well, as I had described in my original thread, the carbs were grossly out of synch, giving the impression that the engine was running on two cylinders only. I removed the rear carb (which was drawing more air than the front one) and realigned the throttle plate a bit. It was a subtle change, but it improved things significantly and allowed decent synchronization. Both throttle bores are somewhat worn (tips on how to fix that are welcomed), so idle speed isn't quite as low as I would like it but it's acceptable for now.
Bottom line: It never ran on only two cylinders, but the symptoms were such that I thought it did.
Hope this might help the original poster scratch another item off the list...