Starting my engine on a stand, issues arose Options

[malcolm2]

@mark henry

Curious if you have used a Uni-Syn. That's what I've always used and had great luck with that.

That Uni-SYn looks totally different. Does it work the same? Looks like it just sits on top of the barrel.

Several on eBay for 1/2 the China one. I have a raised dis-taste for all things Chinese. I am sure you know why.

[Superhawk996]

Sorry but to encourage this is irresponsible

Your overall point is valid. But, at this point he's comitted and has already spun it over to build oil pressure and it runs rough that much we know. At the beginning we all start somewhere. Hopefully on lawnmower, go carts, 2 stroke dirt bikes . . . whatever . . . that are less costly to fix if need be.

Are there risks? Yes, but they are limited. I rebuilt my 1st teener engine at 22. It's not rocket science. Tom Wilson book clearly lays out what needs to be done. If one can follow a detailed recipe and have a sense of self imposed quality control, it is pretty easily done. Luckily, I started with a fresh new set of Webers and guidance from someone in the know to guide me. It was a 1.7L converted to 1911 and it all turned out great!

Engine won't melt down on a test stand with no load unless it's being run at WOT for extended period and running lean and/or detonating. Seems OP at least realized something is wrong stopped to investigate. That is the correct thing to do.

Previous post by Mark Henry is a sound plan of action and clearly outlines the preconditions that need to be addressed before trying to run it again.

[Superhawk996]

That Uni-SYn looks totally different. Does it work the same? Looks like it just sits on top of the barrel.

Several on eBay for 1/2 the China one. I have a raised dis-taste for all thing Chinese. I am sure you know why.

Mine is ancient and pre-dates the el-cheap China imports. Probably made in Taiwan though back in the day - I'll have to look.

The concept is the same. It measures a baseline airflow. I think it may be a bit more adjustable but since I've never used a snail, I can't say that with any certainty.

It works on flat faced carbs without the need to insert into the venturi or velocity stack. I think you may be able to more precisely control the restriction it presents to the carb during measurement but at the expense of losing vacuum signal that moves the indicator up and down in the sight gauge.

Other than that, everything Mark laid out for you applies.

I was just curious why the snail type was his preference. I see absolutely nothing wrong with the snail type either.

[thelogo]

Sorry but to encourage this is irresponsible

Your overall point is valid. But, at this point he's comitted and has already spun it over to build oil pressure and it runs rough that much we know. At the beginning we all start somewhere. Hopefully on lawnmower, go carts, 2 stroke dirt bikes . . . whatever . . . that are less costly to fix if need be.

Are there risks? Yes, but they are limited. I rebuilt my 1st teener engine at 22. It's not rocket science. Tom Wilson book clearly lays out what needs to be done. If one can follow a detailed recipe and have a sense of self imposed quality control, it is pretty easily done. Luckily, I started with a fresh new set of Webers and guidance from someone in the know to guide me. It was a 1.7L converted to 1911 and it all turned out great!

Engine won't melt down on a test stand with no load unless it's being run at WOT for extended period and running lean and/or detonating. Seems OP at least realized something is wrong stopped to investigate. That is the correct thing to do.

Previous post by Mark Henry is a sound plan of action and clearly outlines the preconditions that need to be addressed before trying to run it again.

I just hate to see this guy end up like the other guy who had too build his second $$$$$ big /4 because a rod bearing was not secure and melted the thing down .the 1st time around.

Dont learn on a type 4 build a few dozen stock 1600s
And then tweak your teener engine.

Its way cheaper to get a experienced person then to screw it up

[malcolm2]

Sorry but to encourage this is irresponsible

Your overall point is valid. But, at this point he's comitted and has already spun it over to build oil pressure and it runs rough that much we know. At the beginning we all start somewhere. Hopefully on lawnmower, go carts, 2 stroke dirt bikes . . . whatever . . . that are less costly to fix if need be.

Are there risks? Yes, but they are limited. I rebuilt my 1st teener engine at 22. It's not rocket science. Tom Wilson book clearly lays out what needs to be done. If one can follow a detailed recipe and have a sense of self imposed quality control, it is pretty easily done. Luckily, I started with a fresh new set of Webers and guidance from someone in the know to guide me. It was a 1.7L converted to 1911 and it all turned out great!

Engine won't melt down on a test stand with no load unless it's being run at WOT for extended period and running lean and/or detonating. Seems OP at least realized something is wrong stopped to investigate. That is the correct thing to do.

Previous post by Mark Henry is a sound plan of action and clearly outlines the preconditions that need to be addressed before trying to run it again.

I just hate to see this guy end up like the other guy who had too build his second $$$$$ big /4 because a rod bearing was not secure and melted the thing down .the 1st time around.

Dont learn on a type 4 build a few dozen stock 1600s
And then tweak your teener engine.

Its way cheaper to get a experienced person then to screw it up

Dude, Why so negative? You don't hate to see it, you hope it happens! that is why you are here, lurking for bad news.

You know nothing about me, about my background, my situation, or this engine. This is not my first rodeo. I have screwed up before and I will screw up again.

So take the advice of everyone's grandma and " if you don't have something nice to say, STF".

Here you are in the "garage" giving people advice to " pay someone else to do it" Well find that forum and go play big boy with them.

I am here to learn from the experts and the people that are willing to pass on their mistakes.

And I do thank THEM for chiming in, you?? not so much.

[thelogo]

Sorry but to encourage this is irresponsible

Your overall point is valid. But, at this point he's comitted and has already spun it over to build oil pressure and it runs rough that much we know. At the beginning we all start somewhere. Hopefully on lawnmower, go carts, 2 stroke dirt bikes . . . whatever . . . that are less costly to fix if need be.

Are there risks? Yes, but they are limited. I rebuilt my 1st teener engine at 22. It's not rocket science. Tom Wilson book clearly lays out what needs to be done. If one can follow a detailed recipe and have a sense of self imposed quality control, it is pretty easily done. Luckily, I started with a fresh new set of Webers and guidance from someone in the know to guide me. It was a 1.7L converted to 1911 and it all turned out great!

Engine won't melt down on a test stand with no load unless it's being run at WOT for extended period and running lean and/or detonating. Seems OP at least realized something is wrong stopped to investigate. That is the correct thing to do.

Previous post by Mark Henry is a sound plan of action and clearly outlines the preconditions that need to be addressed before trying to run it again.

Guess this guy should stf up too .

Op. No class man

[Mark Henry]

I've used both uni-sync and the snail (STE), I prefer the snail. That said I only used the uni-sync once back in the mid 90', didn't really like it, It didn't work on weber DCNF carbs, so I sold it in short order and bought a STE snail. For other cars the snail is more adaptable, mostly using simple plastic cups, that's how I do Solex Kadrons.

The cheap china snail is OK for the home shop use, but be careful with it, as it won't take the abuse of even semi-pro garage operation.

Although I do read his posts from time to time there's a reason I have one and only one member on ignore.

[nditiz1]

Do yourself a favor and get the german STE, especially if you are going to stick with carbs. It is the one tool you will use over and over again.

Perry's mini guide is a pretty good baseline.

Since we don't know the condition of these carbs it is very difficult to help diagnose the issue. If the jets are clogged you could experience some of the symptoms you have expressed. I have even seen the same rev drops on a single 34PICT-3 (Beetle carb)while trying to tune it. Pull the carbs off, take them apart and soak them in some carb cleaner. They sell a 1 gallon can that it can fit into. Buy some carb kits from aircooled.net or another well known site. Don't skimp on the rebuild kits, get a good kit.

Follow the setup guides to get the floats set properly in both carbs. Set the baselines and throw them on. You would be surprised how carbs just a little dirty can really make an engine run rough vs them being a little out of tune. Also, you can run an engine, and technically drive an engine without having the main stacks installed. Give it to much throttle and it will choke the engine as the mains will start to kick in. This is also a great way to test you have the correct idle jets installed.

[IronHillRestorations]

@mark henry

Curious if you have used a Uni-Syn. That's what I've always used and had great luck with that.

That Uni-SYn looks totally different. Does it work the same? Looks like it just sits on top of the barrel.

Several on eBay for 1/2 the China one. I have a raised dis-taste for all things Chinese. I am sure you know why.

Step #9 from my post (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)

Unisyn restricts airflow and isn't worth the space in your toolbox. If you are going to have an engine with carbs, you need a STE. Can you make it work? Yes but everytime you put it one one of the barrels the engine will start to stumble, not so with the STE

[ri914]

Lots of great info from the 914 experts. I love reading about 914 stuff that has zero to do with my build. So much cool info and the level of help on this forum is top notch.

[malcolm2]

I got the snail version on the way. I just pulled the filter and it looks like the snail one will just fit better. The other type will require taking the filter base off too. and the jets are in the way. I assume those tall brass screws are the jets, right?

Also have some non-metallic plug wires coming. It seems that the flame thrower 3 module requires them.

Removing the carbs tonight and giving them a cleaning. I guess that will be a good time to set up the set screws.

I also found that one bushing on the hex bar is missing.

[malcolm2]

Any ideas on where to find the bushing. I found one for $5 but they want $15 more to ship it. Guess i better call them.

[nditiz1]

You might be able to combo ship with other things you might need like rebuild kits, jets, etc.

If not doing the soaking route, be sure to pick up a couple cans of brake cleaner. Remove everything that you can, especially the adjusters with rubber gaskets (the brakeclean likes to eat them) Shoot the cleaner into every port. You can even fill up the bowls and activate the squirter pump by hand to get the cleaner to flow through. I usually follow up with an air tool through the ports. Reassemble and set your baselines. Leave the linkage off until you are almost ready to drive. You will not need it for any tuning except ensuring the carbs are in sync off idle. This is where the snail will help as well. When you get to that point you can hold the idle slightly open at like 1500 -2000 rpm and check that both sides are drawing in the same amount of air. If they are even you know your carbs will be in sync while driving. Again this is the last step before taking it out. The only other adjustments will be with the jetting, but if you start with the base of the carbs (assuming Weber 40 IDF) You should be at:

Vents 28
Idle 50
Main 115
Air 180

[914Toy]

Here's my carb tuning procedure from a March 03 post:

Assumptions: the carbs have the optimum jet and venturi package (if you have an unknown engine/cam good luck on this one), the float level in the carbs is correct, the cams are correctly timed, the valves are properly adjusted, the ignition timing is dead on, you have the proper spark plugs for your engine, the linkage is good, the fuel is good, the engine is good.

Remember that the mixture and air bypass adjustment screws are precision needle valves, not head gaskets. Use your fingers to tighten them, not your fist.
Start and warm up the engine.
Make sure the two drop links for the throttle linkage are exactly the same length, and disconnected. You can use a 8mm thin ignition wrench to snap them off.
Turn the mixture screws all the way in and then 5 half turns out.
Turn the air bypass screws all the way in.
Turn the idle speed screws out til it just touches, and then in 3 half turns. (3 barrels I go 5 half turns)
Put on your hearing protection and start the car.
Use your STE and find the barrel that pulls the most. We'll call this one baseline.
Balance the barrel in the other carb that pulls the most with the idle speed screw. (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)
Go back to the other carb, with the baseline barrel. You will have one all the way in, then use the air bypass screws and balance the other two barrels.
Go to the other carb and do the same thing.
Snug the jamb nuts on the air bypass screws.
All six barrels should pull the same amount of air at this point, if not repeat air adjustment procedure.
Snap the throttle linkage drop links back on the carbs. If the idle changes then you need to barely adjust the linkage mounts so snapping the drop links on, doesn't change the side to side idle balance.
Use the hand throttle or a vice grip and rag to lock the linkage between 1400 and 1800 rpm.
Start back at the baseline barrel and adjust the mixture screw in or out, to get the smoothest running and highest idle, then turn it in 1/4 turn.
Do the same with the five other mixture screws.
If you have to turn the mixture screws more than two turns either way (from baseline), you've got the wrong jets.
Recheck side to side and individual air balance, adjust as needed.
Road test the car.
If you get snapping and poping out the intake, it's generally a lean condition.
If you get heavy exhaust fumes, or pboofing out the exhaust it's probably too rich.
If you get a flat spot or popping out the intake at between 2800 and 3200 rpm, you probably need larger idle jets.

That's a rough, five minute draft of my carb tuning proceedure, hope it helps!

If it goes good it should take about 45 minutes, if not about three years.

PK

If it's running good but a little rich, you can turn each air bypass screw out to lean it out some, go a half turn out at a time and test drive. If you have good air balance, just make sure you turn all screws the same amount, and recheck the air flow at each barrel.

This was written 16 years ago before wide band O2 sensors were economical and easy to install, get one it will make your carb tuning much easier.

Excellent clear description with practical application advice. This should be in the easy access library, especially for novices.

[malcolm2]

So with the linkage off, there is no choice but to use both hands to rev the engine? Or am i only dealing with idling here and no need to rev?

[porschetub]

@mark henry

Curious if you have used a Uni-Syn. That's what I've always used and had great luck with that.

That Uni-SYn looks totally different. Does it work the same? Looks like it just sits on top of the barrel.

Several on eBay for 1/2 the China one. I have a raised dis-taste for all things Chinese. I am sure you know why.

Step #9 from my post (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)

Unisyn restricts airflow and isn't worth the space in your toolbox. If you are going to have an engine with carbs, you need a STE. Can you make it work? Yes but everytime you put it one one of the barrels the engine will start to stumble, not so with the STE

(IMG:style_emoticons/default/agree.gif) I was given one years ago and never thought it worked very well,as mentioned it didn't fit on some carbs I had.
I got the STE one and its great with my Zenith's,there is no restriction like the Motometer (Uni-syn ) that I had.
My experience with carbs has taught me to clean,inspect and overhaul if needed before fitting,last set of used Dellorto's I fitted were very clean and looked new on the outside however when cleaning I found dry hard gaskets and bad pump diaphrams,lots of crap in the fuel bowls and elsewhere too.
Also its better to do base line setting before running up and make sure you use new manifold and carb base gaskets.
Good luck to the OP.

[nditiz1]

No need for rev here unless you are setting the timing, which you will want the linkage hooked up. Once you get the smooth idle addressed then you can move into the linkage sync/higher rpms.

[Superhawk996]

@mark henry

Curious if you have used a Uni-Syn. That's what I've always used and had great luck with that.

That Uni-SYn looks totally different. Does it work the same? Looks like it just sits on top of the barrel.

Several on eBay for 1/2 the China one. I have a raised dis-taste for all things Chinese. I am sure you know why.

Step #9 from my post (if you have a Uni-syn, give it to someone you don't like and purchase a STE airflow meter)

Unisyn restricts airflow and isn't worth the space in your toolbox. If you are going to have an engine with carbs, you need a STE. Can you make it work? Yes but everytime you put it one one of the barrels the engine will start to stumble, not so with the STE

(IMG:style_emoticons/default/agree.gif) I was given one years ago and never thought it worked very well,as mentioned it didn't fit on some carbs I had.
I got the STE one and its great with my Zenith's,there is no restriction like the Motometer (Uni-syn ) that I had.
My experience with carbs has taught me to clean,inspect and overhaul if needed before fitting,last set of used Dellorto's I fitted were very clean and looked new on the outside however when cleaning I found dry hard gaskets and bad pump diaphrams,lots of crap in the fuel bowls and elsewhere too.
Also its better to do base line setting before running up and make sure you use new manifold and carb base gaskets.
Good luck to the OP.

Wow. Never realized there were so many Uni-syn haters. (IMG:style_emoticons/default/laugh.gif) I clearly missed the reference in the early post from @IronHillRestorations .

Honestly, I used mine for multiple carb types (down draft & side draft) without issue. The center post is adjustable and can be adjusted to minimize restriction but at the loss of venturi effect that determines where the indicator is in the sight glass. Since all measurements are relative, I tended to use mine with the indicator low in the sight tube to minimze the restriction to the carb.

But in the spirit of learning something from the tribe, I'll get a snail when I get back around to putting a set of Dell's on one of my next engines. Then I can try both back to back. Unfortunately for OP this is a year or so off for me.

Thanks for all the feedback though! (IMG:style_emoticons/default/biggrin.gif)

[ndfrigi]

@malcom2

check the ff link to give you more idea

http://www.redlineweber.com/html/Tech/idf_...nt_controls.htm

https://www.carburetion.com/weber/adjust.htm





Last week I test run my engine on my garage floor and a little rough idle. So I ended up rebuilding/cleaning them and lots of dirt inside (acquired the 36 IDF used along with the engine). I think it is pretty straight forward to clean this carb but I have no much idea with jet combinations. I just assumed the jets on it will be fine since this was a running engine with the current set up.

[nditiz1]

What size engine are those on? @ndfrigi

220 Air
145 Main - this is a little rich for a 2.0
50/55 idles will be good, I can't tell which you have

For anyone interested in the tuning of carbs especially for a type 4 engine. I found this guy on youtube and while he is using knock off carbs (Weber IDF clones) his testing and methods on setting the floats, jetting, and setting up the carbs is pretty sound.

youtube channel -
Motor7710