very frustrated out of answers 18 hp Vanguard in MaxIV

[eddieb1965]

Adjusting valves is easy.Pull the spark plugs and start on one valve at a time.bring to top dead center (both valves fully closed).Now put a plastic straw in the spark plug hole and rotate engine till the straw drops 1/4"(the piston is 1/4" down after top dead center).Adjust valve to .005 and lock it down.Do this to the other 3 and you are done.This is a very simple procedure and takes a metric allen wrench,metric box wrench ,feeler gauges,plastic straw.Just ask if you have any further questions on this procedure.

[westkymaxiv]

ok thanks..
The guy that was gonna work on it told me he still needs to look at it.. that i dont need to run it. He said something is wrong that made the pushrod come out that i would destroy the engine running it.. what do you all think now? I told him i bet the valves have never been adjusted and are so bad out is why it came out.?

[jerseybigfoot]

Is this Mechanic ??? familiar with Briggs Vanguards? He should Know that valve sticking and loosing a pushrod is a common problem for laid up Vanguard engines. And no if you loose a pushrod it will not destroy the engine. Trust me the intake valve stems just got varnished up. Valves out of adjustment due to wear will only make noise and do not create a big problem in performance. They would have to be terribly mis-adjusted (not worn)for the push rod to pop off the rocker. Over tight rockerarms that have not been adjusted properly are a problem with loos of compression and and other issues. Dropping a valve seat is rare and your engine would have to have overheated or run lean for a long time to drop a valve seat and that would be an exhaust not and intake.

[westkymaxiv]

hmm never met the guy . Napa guy gave me his number, then I ask my boss, that use to be an Argo dealer and he gave me the same guys number. But I like what your saying. Plus it is running great except for a slight hesitation. Im gonna adjust the valves and see how it goes. Thanks for all the help.

[westkymaxiv]

ok i do have a question. The manual says to Set No 1 Cylinder @ 1/4" past TDC COMPRESSION STROKE. How do I tell compression stroke? does this mean ever other TDC is the wrong place to se the valve clearance?
I tried to set it still had a slight hesitation. When I had the plugs out one was buggered up on the end and the little contacts mashed together. I had the Bosch+4 4418 plugs in the machine. I had read somewhere they are better.I put 2 new +4 bosch plugs in the machine. It did seem to run pretty good. I did hear one back fire once while running and it also backfired when shut off. I check to make sure new +4 plugs were still ok after running and they are. Also checked to make sure push rod was in and it was. I also adjusted the float a little once and seemed to help the hesitation some. Maybe it needs more. Also the engine seemed very hot to me. Couldnt touch the valve covers when i parked it.

[westkymaxiv]

i think i finally figured out how to find TDC compression stroke and atempted to set the valves again. Fired it up and still had the slight hesitation. after it ran a little bit oil has started spiting out of the hole where the breather hose connects i fear something worse is bout to happen to this engine. It spits enough oil it gets on the muffler and the side of the body. you could also see some on the floor. I did not over fill and checked oil it is right on the mark.

[Tomo]

HI,
Lets start from scratch
Checks [engine history unknown]

compression approx 8 cranks each cylinder approx 130psi considered low but decompression is operating

CHECK with cylinder leak down U will see the issues typically worn rings/bore

Due to history and or age slight compression leak past the valves is likely .Not always detectable by conventional methods

RECTIFICATION
Have heads serviced eg valve grind etc

The problem of hesitation is common if the engine has some age/hours
and fails the leak down test
WHY When the cross hatch /hone marks disappear the cylinder does not seal as good but what most people donot think of is the cylinder therefore demands less fuel from carb [it sucks less] This creates a lean condition when accelerating and therefore the engine bogs .
Remember briggs carbys are not originally designed to operate in an accelerating enviroment such as 6x6 either

IDEALLY a accelerator pump equiped carb is best

tomo

[Bazooo guy]

Or you could pull the briggs and install a 2 stroke.

[Dwayne]

Hi sounds like you having frustrating time .I fill like a goose but this is what happend what makes it worse is I build race engines for motor bikes. My max11 was brand new 2011model kolar 23hp had done about 120 hrs motor started running a bit strange lacking power then sort of come good but slowly got worse started flooding run alright with air filter off then wouldn't rev up with it on started spitting fuel out top of carby so the problem slowly got worse . So I pull motor down looking for sticky hydraulic lifters or brooken decompresser on cam witch I found they don't have .put motor back together problems stile there then a thought took off exhurst presto runs like a beauty .Cut exhurst open to stupid plates spot welded come lose block up exhurst well I fill like a goose with four other mechanics trying to figure it out .Give this a try you may be surprised

[jerseybigfoot]

Slight hesitation with a Briggs Vanguard is common especially if you are running it with the governor connected, richening the idle mixture helps a little. oil blowing through the breather pipe is a common problem even with new engines. This often occurs when you are climbing a steep grade, climbing out of a ditch etc.. You can check the breather reed or disc valve located between the cylinders to see if it is gummed up. if it does not close it will constantly blow oil. Also once oil gets into the chamber above the reed valve it takes a while to clear out. Typically senereo is the oil gets into the breather then coat the filter, creates a restriction in the filter and filter housing has a slight vacuum. This additional vacuum just sucks more oil into the carb and the engine smokes and looses performance.
Suggest you remove the breather and clean it good or replace the reed valve. Put in a new air cleaner if it is coated with oil. Briggs engines are quite durable and catastrophic failure is rare if they are properly maintained.
Badly worn rings will give you additional blow-by but you will notice a decrease in power and will overheat easily under load.

[westkymaxiv]

I checked the oil this morning and its a little above the full mark. When I changed the oil i bought the Brigg container that was the 1.5 quarts. And poured it all in there. One thing I did do to try to get the hesitation out was turn the knob on the side of the carb. I guess this was the air mixture? Maybe I got the mixture off and it was putting gas in the oil? It sure helped the hesitation? thanks for all the help guys I will get there sooner or later or blow it up one!

[Flying Bone]

all i can say is wow! lol.

[Coop]

For what it is worth, I'll chime in here. I've worked on the Briggs engines for many years, I'm quite familar with the Vanguard twins. You say your mechanic is saying to look under the spring. What he is probably wanting to know is if the valve guide has moved. This usually happens if the engine is overheated, the guide is pressed into the head, if the head gets to hot, it expands at a different rate than the guide and the guide moves with the valve. The guides are just pressed into the head. Usually what I've seen that will cause the engine to overheat to this degree is insuffecient air flow over the head. If you haven't done so already, remove the blower shroud, check for a critter nest in there, usually near the coil(s). If the guide has moved, yes, you will need a new head. When the guide moves up, the rocker arm will hit it and stop, usually bending the pushrod and/or breaking the rocker; when the guide moves down, the valve will not close fully, and the pushrod will come off the rocker without getting bent,(usually). TDC is when BOTH intake and exhaust valves are closed.

If you have excessive blow by, which it sounds like you do, you'll have a hard time getting the engine to run correctly, no matter what you do. A blown head gasket can also cause blow by if it is blown into the cavity where the oil returns to the sump, rare, but I have seen it on a Vanguard. You need, as has already been suggested, to have a cylinder leak down test done, this will answer where any leaks in the engine may be occuring.

That "knob" on the side of the carb was probably just the idle speed screw, has nothing to do with air.fuel mixture.

Hope some of this helps...

Coop

[westkymaxiv]

thanks Coop,
this sounds like what the guy was lookingfor to see if the guide had moved. I will take another look to see if I can tell. The screw is described as idle mixture screw in the manual. Not the idle adjustment. It never did this till I started turning that screw. It was sitting still in my garge when this started. Is the cylinder leak test the same as compression test? I have a compression gauge. What readings should I look for? Or should I say hope for.

[Coop]

If that was the idle mixture screw, it should be turned out from seat about 1-1.5 turns. A compression test is not the same as a leak down test, requires different gauges. Basically, you put air into the cylinder thru the spark plug hole and measure how much and where it comes back out of the engine: past the rings, past the valves, etc. Any small engine shop that knows what they are doing will have the equiptment to do the test.

Coop