National Rider

[lefty]

Briggs
170402 0679-01 6912291
Machine Serial: B 30-2743
Machine Model Unknown.

So I have this machine, the first machine I can remember as it was purchased by my dad and I learned how to mow the lawn on his lap with this machine. A few years ago, before I had the help of you fine folk or the knowledge I possess today, I had it running for a bit but not well.

This has a flowjet type carb that I did a kit on but fouled her up apparently during the process because I had to install a fuel shut off to prevent a fuel leak after shutting down.

So today, I pulled it out of the shed since I've developed an obsession and don't currently have anything to work on.

I thought the prudent step would be to verify proper compression, given the age, so I did a leak down test. My compressor put in about 88lbs with 80 on the out side, so I'm guessing that's about 8-9 % loss, which is acceptable based on what I've read. Actually, I think that's pretty good given the age of the engine.

I checked out Briggs site and I think the engine was manufactured in 1969.

Spark was good but I figured I'd clean the coil and magnet on the flywheel anyway since I figured it could hurt.

I'm about to dive into the carb again because it's been a few years since this thing ran.

I was wondering if anyone had any advice as I begin, working on a machine this old. I really want to get this one going and am willing to spend money. I can't seem to find the carb and if I did, I'm sure it would be expensive but am willing to spend the money given the history.

The reel assembly, as I'm sure you've noticed, has been removed. I got rid of it as it was a hazard to my small children and super expensive to sharpen. I plan on using it as a tractor or just ride it around for fun.

I've attached some pics.

[RoyM]

Yup it's an oldie. Your code number tells me December 29, 1969. If the float and needle are in good shape a fuel leak at the emulsion tube ( long brass nozzle) could be the culprit. Remove the nozzle, grind the threads off then coat the tapered portion with a dab of valve grinding compound. Insert and work it back and forth with a screwdriver. Completely disassemble the carb, thoroughly clean and replace the nozzle which by the way is no longer included in the overhaul kit.

[Fulltilt]

Briggs
170402 0679-01 6912291
Machine Serial: B 30-2743
Machine Model Unknown.


Spark was good but I figured I'd clean the coil and magnet on the flywheel anyway since I figured it could hurt.

I'm about to dive into the carb again because it's been a few years since this thing ran.

I was wondering if anyone had any advice as I begin, working on a machine this old. I really want to get this one going and am willing to spend money. I can't seem to find the carb and if I did, I'm sure it would be expensive but am willing to spend the money given the history.

What for? It's a waste of time...you know it has points, right?

The carbs are avail on fleabay, both OEM $$$ and dirt cheap china, which , by the way, Ive used a couple on Tecumseh with excellent results. 12.00 vs 85.00 pretty much a no brainer on older stuff.
Also used a couple of bootleg rebuild kits for your type carb, equally good results.

There should be some repair info/tips around here somewhere from when Bob was running the show. Then there's this previously linked to site, which you say you use a lot : http://outdoorpowerinfo.com/repairs/
The briggs manual has a rundown on rebuilding them. As I said before I usually will burnish/clean the brass seats, but they can be replaced also. Most kits have the seats, just be aware that the gravity seat has a larger needle opening.

[lefty]

What for? It's a waste of time...you know it has points, right?

Because they were filthy and they're part of the ignition system...and I like having shiny faces on my stuff. I'm guessing I didn't cause any harm. I am aware there are points because of the kill method and wire leading from the coil behind the flywheel. But unless I have to, I don't want to remove the flywheel.

I have two things Fulltilt, interest and time. Whenever I'm working on an engine, no matter what the outcome, I never feel like I'm wasting anything.

Thanks for the tip on the carb.

[KE4AVB]

Few pointers.

1. This FloJet doesn't have replaceable nozzle seat nor needle seat or at least I don't see any listed in the IPL.
2. Be aware the main mixture assembly in some aftermarket kits is not threaded properly. The last one I install couldn't even tighten up to stop leaking; ended up replacing it with the OEM version.
3. While you got the carburetor assembly off pull the breather cover and check the valve clearances as these old L-heads tend to close up the clearances leading to non start conditions as one of the valves does fully close at the right time; usually the exhaust but have seen a few intakes too. If they are needing adjustment then it time for a valve job.

[Arkie]

Lefty:
Was that rig a old reel type mower?

Seen a guy get a finger cut off permanently, no reattachments back then, in one of the Briggs engine powered reel mowers few years ago. Whacked it off like a sharp axe, so fast it took little while for it too start bleeding.

Do some online reviewing and searching about info for your flo-jet carb. Not much to them inside but
I've been into quite a few of them old crusty inside flo jet carbs and could usually bring them around if Bubba had not been there first ruining the jets, etc. One part had to be installed/removed before another, had to do with the jets, I think.
If I find the link or info I post it up for you later.
You do need to put a fuel cutoff on that one even with a new carb.

You will have to be careful on a replacement size that is compatible with your engine because they were used on several different HP engines Briggs and Tecumseh. Briiggs also used some flo jets on their vertical engines.
I also had some real old Briggs Service manuals that had service info on the old flo jet carbs. Some of the guys on here might can refer you too a Briggs service link, but I found some good service info online also with pics.

The last time I checked the Briggs replacements flo jet carbs were priced high than gold and a kit was not very reasonably priced either..
Checking price/availability of a replacement carb or kit FIRST results in me being little more careful when trying to restore one.

Here is one link with some good Service info about the small and large flo jet carbs.
If the link don't work go to outdoor power eq>repair index>Briggs carbs, etc.
Lot of good info about all kinds of stuff at this site with good color pictures, step by step. scroll down until you find yours, their are several different versions of the flo jet carb's on this site..
http://outdoorpowerinfo.com/repairs/#id_briggs

[lefty]

Lefty:
Was that rig a old reel type mower?

Seen a guy get a finger cut off permanently, no reattachments back then, in one of the Briggs engine powered reel mowers few years ago. Whacked it off like a sharp axe, so fast it took little while for it too start bleeding.

I hear you Arkie. I actually junked the reel a while ago. It hadn't ever been sharpened and the cost to do so wasn't worth it. I had two little children at the time who got into everything and was afraid they would lop off a finger. Beside, I'm just happy having the machine around as a light tractor.

So I took the carb apart and it was pristine. Probably because I cleaned and rebuilt it about 4 years ago before draining it for storage. At the time, it ran but not well, which I'm guessing now is due to a carb adjustment. Especially since I know much more now and had a successful leak down test. I also plan to check the valves like KE4 suggested.

Regarding disassembly, you are correct, the emulsion tube has to come out first before taking the bowl off because it runs diagonal up through the bowl into the main body of the carb.

So as I said, it ran rough last time. I had set the screws to the start point based on outdoor power equipment but after reading KE4AVG's post, I'm thinking maybe the main jet was seating completely, which may have given me trouble on adjustment because it looks like I may have replaced that. With all I've learned over the past few years, I'm going to tackle this again. I hope to report back with good news.

[lefty]

While you got the carburetor assembly off pull the breather cover and check the valve clearances as these old L-heads tend to close up the clearances leading to non start conditions as one of the valves does fully close at the right time; usually the exhaust but have seen a few intakes too. If they are needing adjustment then it time for a valve job.

Right on KE4. If my research was correct, I'm in spec on exhaust but off on the intake. I'm .010 on exhaust, which appears to be dead center the spec range of .009-.011

But I only have .0025 on intake. Spec range for this intake should be between .005 and .007

As a reminder, the numbers on this machine are:
170402-0679-01 Code: 6912291

Briggs had a parts diagram for 170402-0679-99, which I assume means that it's for all models with type suffix up to -99. Please correct me if I'm wrong.
If I'm correct, a new intake valve appears to be about $10.

I know some have mentioned that you can grind or file the valve stem a bit to win back some clearance. But at only $10, I was wondering about a new one if anyone had an opinion.

I already have the gaskets for the job. I bought the whole kit about 4 years ago when I first started tinkering with this one.

Thanks for the help. As always, all advice is welcome and appreciated.

[bgsengine]

Briggs had a parts diagram for 170402-0679-99, which I assume means that it's for all models with type suffix up to -99. Please correct me if I'm wrong.
If I'm correct, a new intake valve appears to be about $10.

I know some have mentioned that you can grind or file the valve stem a bit to win back some clearance. But at only $10, I was wondering about a new one if .

You will still have to grind down the valve stem and lap in the valve either way - new valve will probably be a tad longer than the original and require more grinding - you'll need a way to keep the valve stem ground square . I'd only suggest replacing the valve with a new one if the old valve face is worn (cupped) or damaged, in which case a new valve *might not* need to be ground (and that cupping wear is caused by dirt passing the air filter)

[Arkie]

Just a heads up when adjusting the valve lash on a l head.

Be careful because you can easily remove too much from the valve stem. They don't seem to be a hardened as Automotive valve stems
Just use a good flat file and in the service manual you will find a ball park clearance with the valve spring off.

If you don't have one already get yourself a Briggs small engine valve spring remover/installer and you will find their is a slight learning curve to re-assembly of valve springs on L-heads especially if you are standing on your head in the dark and the engine is still on the machine and the retainer keeps flying out of the valve spring tool.
If you remove both I keep the associated springs and keepers with the same valve they were used with.
If the keepers are the old two piece tapered type, I use some grease on the first keeper and set it in place on the valve stem using a small magnetic screwdriver blade tip and then go to the other the same way, easy to set and they remain in place as the tension is released from the spring retainer.

IMHO: Since the leak down was ok just do a visual of the valve and not replace. Clean the carbon and go back with new head gasket and torque per sequence and specs. Keep a heads up on the two head bolts by the exhaust ports, they sometimes gall and will twist off if not aware. Use a 6 point box end wrench so as you can see and feel them loosen instead of just jumping on them blind. If they are stuck do the hammer tap to their top and be careful. Clean all the head bolts threads good and I also use a bottom tap in the block holes on some engines and if the two bolts at the ex port are in bad shape, corroded, etc, I install the two galled and rusty head bolts elsewhere and use two good ones in their place if I do not have replacements.. I sometimes use anti-sieze on these two that are on each side of the exhaust port. (the exhaust heat in this area of the block causes them to sieze and gall more rapidly than the others. If you look inside the exhaust port you can see the block offset casting for these two bolts. I've even took a long punch and massaged this area inside the exhaust port to get them to free up on the tough ones. Most generally if you twist one off you are SOL. I've seen some engines run forever with one twisted off and the head gasket not ever blow out, but

While you got the valve spring off pull the valve up little bit and do a wiggle test with your fingers so as to get a feel for a good valve stem and guide vs one that is worn too much. You will eventually get a feel for worn guides and it don't do any good to install new valve into a wore out guide.
Also sometimes the valve stem will have to be cleaned before the valve can be easily removed while rotating the valve. Be patient when re-installing the valve.