Noman Riding Mower , Won't Start

[Dustcha]

Hello Everyone. Glad I found your site. I have a Noma ( Murray) 43 inch mulch/mowing deck riding mower. it has the 15.5 vangaurd ohc engine.
I am getting fuel and getting spark , but the engine won't fire up. It does turn over , but wont crank. i have tested the fuel solenoid and it does retract with the key on. I checked the jet and it was clean also. Any one have any ideas on what I should check for now?? thanks

[Restrorob]

If you are getting fuel and spark but no start, I'd pop the valve cover off and make sure both pushrods are in place and both valves are opening and closing while rotating the engine.

[Dustcha]

pk here is my update, i took the valve cover off and wow- 1 rocker arm was off. I put the rocker arm back on and tightened down a little tighter . I do not know the proper valve lash specs. But I figured the motor would surely crank and run-- but nope it still will not start up.. it still just spins over.

[Restrorob]

Make sure neither pushrod is bent then adjust the valves as below;


Remove the valve cover then rotate the engine over by hand until you reach top dead center compression stroke, Then remove the spark plug. Once at TDC insert a small screw driver in the plug hole touching the piston and rotate clockwise past TDC until you see the screw driver move down inside the hole 1/4". Now loosen the jam screw in the center of the adjustment nut and adjust to .003-.005" both intake and exhaust. Hold the adjuster nut with your wrench while tightening the jam screw. It may take a couple times to get it right because when tightening the jam screw it could throw the adjustment out so check after tightening.

[Dustcha]

Thanks Rob, Well I finally did get it to fire up. but it ran long enough to break the bottom rocker arm into. So I am thinking that the valve adjustment is why it wont fire up. Like I said , I did get it to fire up but that was after I played with the valve adjustment for a while. So now I will try to find a new rocker arm . If anyone has some handy let me know. When I get my rockerarm replaced , then I will set to the specs you gave me rob. I will check back in here daily. thanks

[Dustcha]

by the way, i never touched the nut at the bottom of the stem , just the nut on top of the rocker arm, is that the jam nut? i suppose i still over tightened it .
now by your intructions , do i need to mess with the rocker arm stud nut next to the head -- or just the jam nut on top of the rocker arm?

[Restrorob]

Here's the diagram/procedure for a Vanguard twin cylinder, Use the same procedure for your single cylinder Vanguard BUT use the specs. I posted above.



http://i107.photobucket.com/albums/m314/Restrorob/Briggs/Vanguard%20Twin/BriggsTwinVanguardValveAdjust.jpg

[Dustcha]

Ok rob,, I put another rocker arm on-- and tried it . put the valve lash will not stay where I set it. the jam nut vibrates it self undone with in seconds.. Rob. My head does not use a hex wrench. My head the only adjustment for the valves is the nut on the top in the center of the rocker arm on top of the rocker arm stud. I have noticed that I can back the rocker arm stud out some , then i can tighten the jam nut on top of the rocker down tight and keep my valve lash. I just am not sure if I am supposed to back the stud out any. The stud do have a nut made onto the bottom of them. It appears the keep the guide plate tight, the push rods run thru opening of the guide plate. If i back the studs off to where I want them , then the guide plate will wiggle about a 1/2 inch.

[Restrorob]

OK,

Post both the model AND type numbers off this engine.....

[Dustcha]

model 28Q777
type 0636 E1

[Restrorob]

OK,

Here is the proper valve adjustment procedure;

Tighten the rocker stud back down, LOOK inside the center of the rocker adjustment nut. There you will find a torx drive jam screw, Loosen this screw then adjust the rockers to spec then re-tighten this torx screw to lock the adjuster nut in place.

You have a Intek instead of a Vanguard.....


http://i107.photobucket.com/albums/m314/Restrorob/Briggs/OHV/BriggsSingleOHVValveAdjustment.jpg

[Dustcha]

10-4 rob. I happened to find that set screw out the hard way. haha
Yes you are correct, it does have a set screw and it was not noticeable.
Ok so if I set the valve lash like the directions you displayed show-- it shows difference for intake and exhaust--- how do I know which valve about the Vanguard and intek thing--- on top of the engine on the cover it has label that says vanguard-- it has a red engine cover.

[Dustcha]

ok i think i got it the top is the exhaust and bottom is the intake

[Dustcha]

Thanks Rob---- Mission was a success!!! I now have that mower running great. I could not have did it without your help. I would like to thanks the owners of this site also for giving people like me a place to come ask people with a lot more experience how to fix my equipment. This site and Rob surely saved me some money. Thanks Guys
BTW My mower is a Noma 43 inch riding mower. Noma was bought by Murray which was bought by Briggs. Bad thing is that my model number does not show up in any parts charts. I can get the engine stuff and I can get deck Belts and Blades. but the rest of the mower stuff is hard to get since no one has the model number listed to go by.
the model number on the frame sticker says murray model number F4316060

[Eagle_89]

If you are getting fuel and spark but no start, I'd pop the valve cover off and make sure both pushrods are in place and both valves are opening and closing while rotating the engine.

Excuse me for stepping into the middle of this thread, but i am having a similar problem with the engine not starting but fuel and spark testing good.

When I opened the valve cover, it appeared a mixture of oil and gas came out and when I turned over the engine, the pushrods both cycled, but "fluid" would come out around the lower push rod. I'm assuming this is not normal, but what is causing it?

Thanks for any and all help/suggestions.
Brian

[Restrorob]

Excuse me for stepping into the middle of this thread


Well Brian, Looks like you stepped into the tail end of this one.....


Sounds like the float needle valve stuck or has trash under it causing the carb to flood fuel into the crankcase. If you check the oil I'm sure you will find a higher than normal level and it will smell like fuel.

Take the carb. off then tear it down, Spray carb. & choke cleaner with the straw through ALL ports, passages and jets then blow it out with compressed air if available then re-assemble, Check/clean the fuel tank and flush/replace the fuel hose and install a new fuel filter. You will probably need to blow the excess oil-fuel from the cylinder as well and replace the spark plug.

Don't forget to change the oil......

[Eagle_89]

Thanks I'll work on that.

Just for my education. Under normal operation should any fluid be coming out here? Oil or Gas? Would any internal damage occur if I keep cranking the engine?

[Restrorob]

It could sling some oil out of the front, The rockers are splash lubricated, There should never be any fuel in there and yes internal damage could accure if ran very long with fuel in the crankcase.