Riding mowers locking up on startup

Discussion in 'Other Repairs' started by Kutter, Apr 19, 2006.

  1. Kutter

    Kutter New Member

    Messages:
    5,379
    State:
    Arnold, MO
    I have two mowers, both Brigs. One is an 18 hp twin and the other is a 9 hp. Neither would start this spring. Batteries checked out fine. New gas. Both have the same problem. The 18 can barely be turned by hand. The starter doesn't have enough power to move it at all. When I turn it by hand, if feels like it is so tight with compression that it won't move hardly. When it does move, it moves ok till it reaches a certain point, then locks up again. I pulled the plugs and the starter can turn it fine.
    The 9 hp is doing the same thing. Twice earlier this spring, I was able to start it, with a jump from the charger/booster. Now it won't start even throwing high amp booster to it.

    Any idea's out there?
    Thanks
     
  2. YeeHaw

    YeeHaw New Member

    Messages:
    446
    State:
    Quincy Illinois
    We had that problem with our old cub a couple years ago. My dad opened up the battery compartment and he messed with some wires that were disconnected. We had to take a pair of pliers and touch something with them, we can't remember what it was but it made a lot of sparks, but started up. Hope you can find the problem, don't know if this info will help you though.
     

  3. Kutter

    Kutter New Member

    Messages:
    5,379
    State:
    Arnold, MO
    At this time, I'm thinking that the problem won't be in the electrical area. With the flywheel too tight unless the plugs are removed, it sounds more like a stuck valve or something simular.
     
  4. lawnman61

    lawnman61 New Member

    Messages:
    1,694
    State:
    Fort Worth, Tex
    I deal with lawn mower problems every year and I used to own riding mowers with briggs engines and always had problems with the valves sticking. So I quit using briggs engines and went with Kohler engines with oil filters and I have never had that problem again.
    Chances are, your engines are vapor locking or you have very sticky valves.
    That is what most of the problems are with Briggs engines 9hp and higher.
    Also you should make esure you change the oil on a regular basis and use
    10w30 engine oil not straight 30 weight and don't use cheap oils.
    Thats the best I can tell you.

    AL
     
  5. olefin

    olefin New Member

    Messages:
    3,908
    State:
    Texas
    Strange, I don't mean to be question you but:
    I've never used a multi-viscosity oil in a mower. Only straight SAE 30.
    Been using mowers for 48 years. I've purchased 3 Sears mowers, 2 of those are still being used today. Never touched the engines other than oil changes, air filters and a few plugs, starter ropes etc. Last year I did have to replace the flywheel shear pin after hitting a tree stump.

    The manual for my newest mower says: 5w-30 for operating temperature below 32 F. SAE 30 for temperature above 32 F.
     
  6. FS Driver

    FS Driver New Member

    Messages:
    2,323
    State:
    swansea,illinoi
    tom ,
    i would drain all your oil
    and fill your crankcase with marvel mystery oil and turn that puppy over with the plug out over and over a few hundred times then drain the stuff
    (i would resave this for just this sort of thing again).
    then fill it with your regular oil you normally use and see what happens
    that marvels will loosen stuck valves .
    i put a smidgen of that in my gokart and generator lawnmower riders and truck crankcase.
    its good stuff.
    they even have gas treatment i have used it before also periodically.
    interested to hear what happens with your motor
    how old are these mowers?


    also i agree with dayton i just use reg 30 weight and also a pushmower needs NON detergent oil
     
  7. ShovelHead

    ShovelHead New Member

    Messages:
    11
    State:
    ohio
  8. ShovelHead

    ShovelHead New Member

    Messages:
    11
    State:
    ohio
    I have had the same problem before. I baught a mower(briggs engine) from a neighbor and let it set over the winter. I would not start the next spring. I had seen the mower work just before i baught it. I asked the neighbor if he had any idea why it may seize up. He didn't have a clue. I decided to rebuild it and when I was putting it back together I found that there were two problems. One of the valve stems was bent and the top of the valve had a burr on it. This clued me in on a few things. One the mower didn't shut down righ away when you killed it because of the gap between te valve and the valve seat, and two the vale stem was bent in my opinion because the wrong oil was used( I later foud out there was 10w30 in it when I baought it). Or maybe i just had rotten luck!:cool:
     
  9. squirtspop

    squirtspop New Member

    Messages:
    968
    State:
    Glencoe, Arkansas
    I agree with DRC. Had
     
  10. squirtspop

    squirtspop New Member

    Messages:
    968
    State:
    Glencoe, Arkansas
    Had the same problem with the tiller. Removed the head and cranking cover/rope. Would turn halfway by hand then lock up, went the other way about halfway and lockup. Removed the head and sprayed the valves with penetrating oil and just kept working back and forth finally broke loose and working fine
     
  11. lawnman61

    lawnman61 New Member

    Messages:
    1,694
    State:
    Fort Worth, Tex
    I have first hand references that recommend using 10w30 oil in any lawn mower engine and the multi-vescosity oils are actually best for these engines.
    I have been in this business for 15 years and use multi-weight oil in all my mowers. The manufacturers are now using hydraulic lifters in most of these engines and Highly recommend multi-weight oils. "It will not hurt your engine".
    It is much better than your straight 30 wt. oil. If you use the straight 30 wt oil in an engine that has hydraulic lifters in it, the lifters get to tight and you can bend a valve and cause more damage to your engine.
    Non detergent oils are safe no matter what.
    I deal with proffensional people that work on my equipment and they haven't steered me wrong.
    Also, yes you can put some of that Marvel Mystery oil in it and it will lubricate other sticky engine components, it is very good stuff.
    You may have a slightly bent valve and that could cause a valve not to operate properly.
    #1 priority is KEEP THAT OIL CHANGED and clean the air filters and change that spark plug on a regular basis.
    If you don't believe me, just ask TIGER44, he is a member in here and his dad owns a lawn mower sales and repair facility. He is the one that works on my equipment. Just PM him and I'm sur he will lead you in the right direction.

    AL
     
  12. olefin

    olefin New Member

    Messages:
    3,908
    State:
    Texas
    Al, I don't doubt your experience.
    But since I've only had to purchase three mowers in 48 years and two of those are still in service I'll stick with the oil specified in the owners manual. At this rate they may out last me. :)
     
  13. Moon Cat

    Moon Cat New Member

    Messages:
    70
    State:
    Upper Marlboro, Maryland
    If Im understanding you this problem would be described as no crank no start. Try this,remove the spark plug. Move the plug wire as far away from the spark plug hole as possible.Crank the engine with the starter for at least 30 sec. with the spark plug out. Watch the plug hole for large amounts of fuel. If you see excessive fuel (more than a small mist) your engine may actually be hydro locked with gasoline in the cylinder.The piston can not compress a liquid, like it can a fuel air mix (vapor) Also check the engine oil level if it seems to overfilled it could be because that excessive fuel is migrating into the engine oil.Change the oil if it comes out real fast and seems real thin like water its because its dilluted with fuel.Hydro locking usually occurs because the fuel inlet needle in the carb. is not sealing properly or your carb. float is not floating. The carb. dumps to much fuel in a liquid form. And hydralicly keeps the piston from moving to the top of the cylinder both valves are closed and wham it stops. Be carefull when trying this because the plug wire will still spark and could ignite the fuel blowing out the plug hole. I have seen this hapen often in Briggs engines . Use 30 weight normal operation use multigrade oil below 30 F.
     
  14. RamRod

    RamRod New Member

    Messages:
    2,047
    State:
    Ohio
    I've seen this problem numerous times. I used to train on small engine repair and found that most mowers like moon cat stated were hydro-locked. Just drain the oil, spray some wd-40 in the cylinder after you take the plug out and crank it over several times. Replenish with fresh oil and you should be back in business.

    FYI as far as motor oil in lawn mowers go, here's an easy way to remember what kind of oil to use. Since detergeant motor oils such as 10w30 have cleansers mixed within the oil, you should only use them on mowers that have an oil filter on them. So if your mower doesn't have an oil filter on it then use straight SAE 30.

    :0a26: ​
     
  15. metalman

    metalman Well-Known Member

    Messages:
    3,457
    State:
    IN
    Name:
    Winston

    What he said!
    I just had this issue myself a couple of weeks ago. A new needle valve in the carb fixed the problem...W
     
  16. zappaf19

    zappaf19 New Member

    Messages:
    1,574
    State:
    Monticello,IN
    I have a Toro ground master. I use mobil one in it because it is thrown into the cyl. faster than reg. oil. We all know that starting any enging is hard on the cyl. because they are "dry" after sitting.
    Bill