I just picked up a used 616 with probably several hundred hours on it.
Where do I find the model number for the engine. It seems to run a little rich and I only found one adjusting screw in the center bottom of the front of the carb. It doesn't run smooth at any rpm, not bad, but not smooth.
I took the carb cover off tonight to see if it was gummed up or full of dirt but didn't see anything out of the norm. I sprayed the carb down and cleaned out what needle jet that I could find. I have a tube that comes off the front top of the carb that has a piece of rubber hose with a screw plugging it. What did this hook up too?
Not sure what I would call the brass tube that connects to the top of the carb that goes down into its own hole when the top is on, but it has several varying size hole, but it was slightly bent so I straightened out and reinstalled the top. Doesn't seem to run any better if not maybe a little rougher and richer with maybe some black smoke.
The model number should either be a sticker or medal plate on the blower housing. Depending on engine could also be stamped in a valve cover or cylinder shield. Assiming Vanguard engine, the carb should have two brass looking fittings on it. One is were the fuel line hooks to and the other should be the carb vent. I have seen people reverse the lines on occasion. I don't think they are reversed from your description. the other brass fitting, mostly likely with a 90 bend in is should be the carb vent. If that is the one with the hose and screw, remove either the hose or screw and see if it runs better. If the vent is plugged for some reason it can cause rich running. I bet somebody plugged the vent because there was gas coming out of it because the needle valve was leaking.
I unplugged the vent so I will see if that makes a difference while running. I only ran it for a little while to see if it made a noticeable difference but couldn't tell anything. The screw on the bottom is screwed out 4 1/4 turns, What is this screw for? I can turn it all the way in without making a difference, this doesn't seem right.
Oh, and by the way it is a vanguard engine. I didn't see a name plate with model number and I didn't see anything on the valve covers. I will look a little better this afternoon.
I picked up a manual for the mower deck and the mower but it appears I have to get a manual for the engine as well. I am going to check the valves to see if they are adjusted correctly. I have done a little searching and found some clearance specs of .012 for intake and .014 for exhaust, does this sound right?
Can the muffler come apart internally? There seems to be a lot of noise coming from the back of the mower, at different rpm ranges, like loose metal shields or something like that.
With all theses questions it sounds like I have a piece of junk, but this thing looks nearly new and mows really well. Just trying to get the bugs worked out
Thanks
Bob
Thanks, I found the model # 303447, I wasn't looking hard enough
Question on adjusting the valves. Tell me if my thinking is off. Usually on finding top dead center I would watch the intake valve open and close then put a rod or whatever in the cylinder and watch it until it gets to the top telling me its a TDC then my valves should be loose right?
when I check my intake with a feeler gauge at .004 it is close but if I push down on the top of the rocker slightly and release pressure it widens the gap considerably to say around .014 does this seem right?
I don't know if its that far off but I would think me being able to push down on the rocker arm and creating more of a gap means the valve is not set right. Keep in mind that I am releasing the rocker with my finger, not continually applying pressure when getting a measurement
Your thinking of find TDC is about right on, but then turn the crankshaft until you are about 1/4" past TDC compression stroke and both valves should be loose. If the gap is changing that much sounds like something preventing valve from seating properly, unless you are picking up on rocking motion from side to side which can cause varying valve clearance readings.
Checked the left side and they seem to be set at about .006 close enough as far as I am concerned. But... I believe there has been some monkey business on the right side which is the first side that I started with. I am afraid that I cant get the valves to adjust far enough in to take up the slack and still leave enough room to tighten the 13mm nut to down, not enough threads on allen head screw. The intake pushrod is different (thicker) looks like a automotive style push rod to me, and the exhaust rocker arm has had some grinding and welding done to it.. I have a thought and wondered if anyone has switched the securing nut to the underneath side of the rocker arm to compensate for the lack of threads. Obviously this isn't the correct way to approach this to fix engine. But... I would like to at least get the rest of the mowing season with it before I have to rebuild the whole dang thing.. I have a picture if I can get it loaded.
As it is set now I was able to get the exhaust set to .004 but the intake is at .018 whats your thoughts on this.
Thanks
Bob
The left rocker has sure been cobbled on. The right side push rod looks like it an aluminum intake push rod out of an intek engine. Should be an fairly cheap and quick job to change out the wrong push rod and the cobbled rocker. For all we know somebody may have ground down the stems on the valves while they were at it.
Something is definitely out of kilter someplace with that setup. Normally the adjustment screws stick out of the top of the locknuts a few threads, or at least level with the nut.
What I am hopping is, I can get a intake pushrod and a exhaust rocker. But looking at the ground on rocker I am thinking it was cut loose from the side moved forward a tad and re-welded thus giving a little more adjustment in the rocker arm. What confuses me is what is wore out causing the lack of adjustment. Cam lobe? Or is it the wrong parts all together? She smokes a bit and doesn't run too smooth. Would a intake valve set at .018 cause it to run rich or a little rough?
Thanks for your thoughts on this
Bob
Too much gap in the intake will effect the timing, causing the valve to open too late and close too early. That much gap could be caused by a push rod problem being wrong push rod. If that isn't the case I would be thinking that maybe the seat has come out. either could cause rough running, and oil usage. Possibly coupled with a blown head gasket on that cylinder.
Misfiring, and low power on one cylinder can and will cause oil usage. Have an uncle with a generator with a vanguard engine that was using a quart of oil every 8 hours because of a bent intake push rod on one cylinder.
running a compression check wouldn't tell me anything would it? I was chatting with my neighbor this evening and I was telling him what my problems were and he said If I needed another engine he had a 18hp vanguard and sure enough he did. It had a coil pack or something go out. I wonder if it would bolt on? I don't have the specs off of it as I am going to focus on the engine I have now. I will look at the valve stem ends to see if they have been ground on. I am still not getting why there was a different size push rod in there and it looks like to me that the tappet or what ever it is called that rides on the cam lobe is made for that size push rod if that makes sense
A compression test may tell you something. Most Vanguards run about 150 pounds if in good condition. I haven't seen any vanguards with aluminum push rods. The ones that I have worked on use the same push rod for both valves.
The Vanguard that your neighbor has should bolt up if they are about the same age. Briggs has changed the blower housing on the newer engines, which may require a different stub shaft to run the drive pumps.
Thanks so much for your knowledge. I did a compression check and found the left side to be right at 125psi and the right side at 130psi. I was kinda expecting the right to be lower. In the process of checking compression I managed to crack the porcelain on the left spark plug so I replaced them and I am thinking it may have smoothed it a bit, or I could be imagining things, still runs well enough to mow and If I can get the muffler quieted down with the loose baffle on the inside it would make me happier. I am going to pursue the neighbors 18hp in hopes that I can check it out to see if it will work and even maybe give it new gaskets.
Would my blower housing interchange with it? The 18 doesn't have the cut out for a drive connection to that side so I will have to change the fly wheel or something
If both engines are the same ago then changing things around shouldn't be too bad. The newer vanquards use a deeper blower housing and taller fan than the previous versions, which may require the longer stub shaft kit.
Got some more questions.. Today I have been mowing and after about a hour or so of mowing the engine would die if I was turning too quick or something like that so my first thought was low on fuel. I went ahead and filled it up even though it had about 1/2 gallon. seemed to run fine for another 1/2 hr but then started doing the same thing so I let it set then checked the oil. Its was about down to the lowest mark so I though, maybe it was causing it to shut down because of a low oil switch or something. I filled the oil and still same thing, when it would start running bad it would sometimes, backfire and if it didn't die I would throttle down and let the engine catch up and it would run fine. Soooo.... I remembered that I unplugged the vent on top of the carb,, Thinking this may have something to do with it so I plugged it back.... Well now I can make a pass then once I start heading down hill, gradual decline it will die and come to a complete halt, then I have to throttle back let the starter crank a couple 3to 5 seconds and it will catch up then start, but sometimes when I hit the PTO for mower it might die....Here's what I have done lately,, changed the oil and filter (Sae30) uses about 1/4 qt a hour,.replaced both plugs and also bought new gas. I feel that it is gas related. I checked what remaining gas I had left in the can to see if it may have had water in it but I couldnt tell. What do you guys think. I am going out to the garage and take the top off the carb to see if there is dirt or something in it.
What should the only screw jet that I could find which is on the front of the carb centered down low be set out?
Couple other details worth mentioning I think, It happened to die in the shop so I pulled the carb top of and found that there wasnt any fuel in the carb, so now I am thinking fuel pump. I pulled the float and needle out and cranked the engine and it would spit a little fuel into the carb but I wonder how much flow should be present. I expect the fuel to really pump out of it but all I got was some spitting and small bubble. I am going to look for faulty fuel lines but they all look new.
What should the fuel level look like it the carb if the floats are set properly? Seemed a little low when I took the cover off to inspect it
