I asked Fish to move my original thread here but I guess it takes time. ANYWAY -
I finished mowing yestrday and the engine started to make a wierd noise - something like CLUNG, CLUNG, CLUNG with a reduction in rpm-s, then back up to normal rpm-s then CLUNG again and so forth.
I started dis-assembly today and the valves are still in one piece. the pushrods were still where they belong, there was no metal filings in the valve chamber.
The upper pushrod with the red stripe was still ok. the bottom pushrod didn't look like the upper one. The ends were polished at the very ends. There was no appearance of the ball end like the upper one.
Its that noise that's got me stumped. Later today I'm going to remove the head.
#2
Fish
Removal of the head won't tell you much, post all of your engine's model numbers here so we know what you have. I am guessing that you may have a counterweight
and the link that mounts it to the block may be broken, but that is just if you have one, which the model numbers will tell us. Or it could be something on the engine top, like broken magnets and alternator.
As far as me moving anything here, they won't let me do anything other than make posts.
numbers off the fan shroud are:
28N707
0166 01
9604024A
#4
Fish
Yep, you have a counterweight, so that is a good possibility. But to verify, you have to pull the engine to see things. But first, drain the oil and look closely for
crumbled aluminum and other metal slivers, etc...
I was gonna pull the engine anyways and clean it up a bit.
I'll do what you said, draining the oil etc and looking.
I found parts available from ereplacements and repairclinic.com
one quote for a counter balance was for $192 and change.
how do you get the magneto off? there's a tapered shaft and a woodruff key.
When I used to work for a guy that crushed cars, he had a bunch of honda generators - and - they would break. The rotor is mounted on the crankshaft on a tapered shaft and one through-bolt. I found that if I could find an open area where the tapered part was, I could give it a sharp rap with a brass drift pin and a hammer, the rotor would pop off the shaft. I wonder if this would work with the flywheel/magneto?
#7
Fish
They have a puller, and two 3/8 bolts near the crankshaft for a puller, it won't take much. just use a standard puller and give it a smack to pop the flywheel loose.
I got the flywheel off without any problems. There were two - 5/16-18 tapped holes, 180 degrees apart. I sort of jimmy rigged a flat narrow access bearing splitter. It had two 3/8 holes in it that just cleared the 5/16-18 bolts. Those with upward pressure on the flywheel bolt provided just enough oomph to pop it free.
Next in order is to unbolt the engine from the frame and get to work on the double pulley and shaft.
In the specs on the model number, there is a letter after the cu in displacement [28N] Is the letter of any importance? Book says it has to do with cylinder head construction etc. The next to last number is a zero - this says [0 - Plain Bearing/DU
Non芳lange Mount - I know what the non flange mount means. What's the DU mean?
#9
Fish
A du bearing is just a thin flange bearing that presses in the bearing area that has been milled to that diameter, nothing like a ball or needle bearing.
Well, got the motor unbolted, belts off the pulley. You guys could've told me that the pulleys wouldn't clear the chassis! Well, the smaller one did however the larger, I couldn't even get it to clear by angling it. So now I got to use a three jaw from underneath the mower to get it off!
But I got to wait. My compressor blew out a sleeve. Repair parts should be here Friday. Then I'll be back in business - I hope!
Oh yeah the crankcase didn't look bulged out so the counterweight should still be in one piece.
#12
Fish
How in the world can we know what you are working on? Briggs makes engines for hundreds of applications....
well, surprisingly I'm glad it came apart so easily. with a puller on the pulleys I heard a snap and the pulley slid right off!
I separated the lower crankcase housing from the rest - no metal filings inside. everything was clean. counterweight was still bolted in place. I'll post some pictures later today.
What's that thing with the plastic gear and what looks like fly balls and a moving sleeve that contacts the governor pawl.
I guess next I'll hafta order new gaskets and a few hardware items and put this sucker back together!
I'm still confused what that clung noise was.
#14
Fish
The part you are describing is the gov/oil slinger.
Were the engine mounting bolts loose? The bearings around the counterweight have any slop?
No, everything is still tight. I did notice that the bolts that hold the crankcase cover on came off without any due force. The engine bolts were pretty tight holding it on the frame.
The pictures I have listed
Remember I said that I had hit a tree stump? After this is when the clung noise started. Well, follow this train of thought -- the two mower blades are spinning at high speed when all of a sudden those rpms are reduced to almost zero. The engine speed goes down but doesn't completely stop. They pick back up and I finish mowing but that clung sound is there. My thinking is that the pulley got slightly bent and was hitting the part of the deck the engine is mouinted on - this is the first pulley, the one that feeds power to the drive wheels. AND the other pulley that powers the blades is down further on the pulley shaft. So this is wobbling a touch, and may be contacting the belt guide rods which are bolted to the chassis. Anyway I ordered a new double pulley.
#17
Fish
I hit a rope near a boat once, and it wrapped around the blades and shut the engine off suddenly once. When I restarted, I had a clunk. The rod attaching the counterweight to the block had shattered, still ran good, but just clunked.
As you can see from the photos, the counterweight is still intact. I took off the outer counterweight and the aluminum link is still in one piece. I don't think much force was applied to the crankshaft to bend it because all the energy to the blades is transmitted by means of a belt which in my thinking would take up the shock of suddenly stopping. 'Be different if the drive was a chain drive.
Question - would a 1/4 inch drive break-away in-lb torque wrench be ok? I can get one 20-200 in-lb. or should I get a 3/8 inch drive?
#19
reynoldston
I will be right next door to you in a couple of weeks. Right in Reynoldston NY, around the corner from you. If you still are having problems give me a call, its always a nice ride down River road.
#20
Fish
To be honest, I only use a torque wrench on rod bolts, some of the time.... I never argue with anyone that wants to do it by the book. Well torqueing the starter top screws, I may give a bit of a hard time....
I got the pulley part yesterday via UPS.
The old pulley had the key separate from the assembly. This new pulley, the key is cast with the sleeve part. [not separate]
Just waiting for the gasket set to arrive.
I got them from partstree in florida.
I got the rest of the parts today. In the gasket set there are three crankcase gaskets and a white platic piece in the shape of a gasket. Is this a shim for crankshaft clearance? I got some synthetic oil, a gas filter and a new plug. There's several parts I didn't recognize when I was tearing it down [O rings etc]
I got a tube of Loctite Blue. Do I use this on all the bolts or just the head and crankcase cover bolts?
#24
Fish
I only use Loctite on the rocker arm studs myself.
They sent you 3-4 different thickness base gaskets to take the up-down play out of the crankshaft.
It's hard to believe that there is a locking screw inside those rocker nuts that hold the rockers in place. I still haven't looked into it.
I will later today. Also, I noticed a cap on one of the valve stems. Now, I don't remember if two caps were used. I put the head in my wash tank then blew out the head. I don't know if one of the caps blew off or if it only used one cap. How canI tell if I need two or just one cap?
I looked at a thread [video] of adjusting valves on a 15hp briggs. There was only one cap on the intake valve. the adjustment specs were the exact match for mine - .003 to .005 and .005 to .007
So, if I can i'll set one at .004 and the other at .006.
I did see the locking screw in the valve ball nut. So now I feel a little more comfortable.
I couldn't for the life of me figure out how the nuts stay in place with all that movement. Now I know. The nut itself screws over the stud and the locking screw presses down on top of the stud.
#28
reynoldston
Sounds to me like you are doing OK. Did you grind the valves and valve seats. I always like to adjust the valves on the loose side or high number.
This is besides the point seeing you are putting the engine together. When I have a engine apart to that point I always just clean the valves and seats with lapping compound. This also gives you a opportunity to replace the valve seals.
put everything back together. hitched up the battery. cranked the engine without the plug in and it was free to turn. hitched up the plug. choked it, set to fast idle. cranked it and it backfired out of the carb. DAMN!
TRIED IT AGAIN AND IT BACKFIRED AGAIN OUT THE CARB.
That tells me that it is firing when the intake valve is open. So, what do I do now?
Shall I take off the air duct and the valve cover and the plug and watch what opens when the magnets approach the ignition coil?
Nothing should happen because the piston is approaching top dead center when the spark is supposed to fire. [compression stroke]
I guess setting the valves has me confused.
Book says to back off counter clockwise when piston is coming up for compression, then adjust the valves.
I have a Craftsman riding mower tractor. The model is a limited VTS and it is light brownish tan. The battery works fine but the mower wont start. Any ideas? We charged the battery but i dont know what is the problem
I have a Craftsman riding mower tractor. The model is a limited VTS and it is light brownish tan. The battery works fine but the mower wont start. Any ideas? We charged the battery but i dont know what is the problem
This looks like your first post on this forum. (Welcome) You might have better luck if you start your own thread under Craftsman. You say the battery is fine. The next step would be check your battery cables and connections. Then if then are OK I would check the starter solenoid, and make sure you are getting voltage to it. If you are not getting voltage to the small terminal check the safety switches. Then if that all checks out it might be a bad starter. This is just a quick run down as to what you can check.
