Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hello,
I have a lawnmover with a tecumseh TVS9043388F engine.(SN 8222A) I'm having a hard time starting it cold. I've repplaced the plug, cleaned air filter, remove carb and bowl, cleaned intake port on engine.(bigh deposit in the intake section on engine) I've also taken the bowl off the carb and cleaned the needle seat, and sprayed the inside of the carb with cleaner and replaced the fuel line. After doing this the mower does run better when warmed up. (now it will stay running on low idle speed and won't stall in the middle of mowing the lawn. I did the seafoam deep creep spray while running the engine and plan to use seafoam in the gas.
This mower is a Murry with a date code of 0729. Any suggestions?

For the SeaFoam.  I've applied directly to varnished bowls and let it set.  It never did anything.  It did not act or loosen built up sludge either.  

 

Not sure by your description if it’s still stalling when on full power and mowing.  Stalling after getting underway could be due to the plug (you’ve changed that) or a blocked vent in the gas cap.  Try running for a while and loosening the cap so air can get in. 

 

You have partly cleaned the carb which is good but not fully.  A better cleaning would be remove it and do a full cleaning with a spray carb cleaner or a dip in a carb solvent tank ( A can of solvent $20 at Autozone.  Comes with a basket).

 

I’m not sure what model you have but if it’s got automatic choke verify that it’s working.  Look in the carb throat before starting.  If no automatic choke then is your primer working?  Sometimes you can look into the carb throat with the air filter off and see what you’re getting for a spray generated by the primer.  You can test by priming many times and pulling several times.  The plug should be soaked.  Most mowers take 2-3 pushes on the primer to get the right amount of gas into the throat for starting.  If you prime and you don’t start the plug should wet.  If dry then suspect the primer. 

 

You can inject a little gas into the plug or carb throat to start a cold engine.  It does not take much.  If you don’t start and the plug eventually gets wet suspect spark.  You have spark probably but it might be intermittent.

 

From what you described it seem like it might be two things.  The primer is not working so hard starting and once running the carb can’t source enough gas so still dirty inside.  If you’ve done a good job with the sprayer getting all the open holes then possibly the dirt is in internal passages so may need a dip in solvent.  Not sure of your carb type but if it’s got a bottom jet there may be holes in the jet that need cleaning.  Possibly you’ve gotten those. 

 

What was the “big deposit on the intake section”?  Was that the carb or a clogged up air filter? 

If you are mowing at full speed then the carb is clean then you likely just have a prime issue.

When I took the bowl off the carb it was clean no deposits.( this is a sealed carb, no adjusting screws) I sprayed all the holes too. The deposit was either fuel deposit or carbon build up. It was in the block just beyond where the intake manifold is attached.
The carb has no choke, just the promer bulb. It seems to be squirting enough fuel.

When cold starting I push it 3 times no start. I end up pushing enough to wet the plug After several attempts I give up and remove the plug dry it off and crank the engine with no plug to clear the cylinder. It seems to have enough spark.

After removing the carbon deposit and doing the seafoam deep creep sray while running the engine, it no longer quits running after it is warmed up and I'm in the middle of mowing and It will stay running on the low idle speed. Before my cleaning attempt it would stay running on low idle ever and now it does. I'm just tired of fighting with it to get it started.

If the engine runs a it should once it's started, I'd guess to say that your primer bulb is deffective or the primer system is blocked somewhere.  You may have to take the carb off to inspect the bulb/primer gallery.

   From what you have described it seems like the primer is ok and your getting gas, enough to eventually wet the plug.  You need gas, air, spark and compression.

   You have gas.  Air is a generally a given.  You say you have spark, it does not run to full speed and there was a buildup by the intake manifold.

   You could have low compression from rings or leaking head gasket.  Possibly your flywheel key is broken and the flywheel moved to change the timing.  You could have intermittant spark (rare) or weak spark.  Check the spark after dark to see if you get a nice fat blue spark.  You could have a manifold gasket leak.  Once you get it running spray some carb cleaner around the joint and listen for a change in RPM.  A doubtful possibility is over priming.  Some snowblowers overload with two primes but not so usual for a lawnmower but worth checking.  Try one prime and a few pulls then check the plug.  

    If you have an air compressor you could dump air into the plug hole with the piston at TDC and listen for leaks.   Carb throat for intake valve leak.  Muffler for exhaust leak, oil fill hole for rings and around the head for a leaking head gasket.

l would make sure u have good compresion, does it start fine when hot?

Yes it seems t ostart fine when warm. I'm going to do a compression test this weekend. I found out the carb rebuild kit isn't available. So if it needs a rebuild I'll need one of those generic rebuild kits.

I own a Sears Craftsman mower with a 4.5 tecumseh engine. I change the primer bulb after a couple of years, especially if the 3x pushing does not start it. The bulb might look fine but it seems to spring a leak at the molding seams especially under the bulb. I am looking at a new Sears mower that has a self primer.