Briggs & Stratton Hard to Start

[RalphVa]

Have JD L120 mower with 20hp Briggs Intek "V" twin and its miserable to try and start....

Did internet search and solution seems to be adjusting valves to .004 for intake and .006 for exhaust.... According to some "compression release" mumbo jumbo with cam...

Well that is not solution. valves are at tight .004 & .006, some people suggest a .003 and .005 but .003 & .005 feeler gauge shows them almost loose... So I believe I'm in the ballpark...

Have gone over engine and its getting fuel, no intake or exhaust leaks, choke seems to work and solenoid on float bowl seems to work....

Runs great, once started....

Any suggestions appreciated...

Dale

This time of year, and really almost any time if it really is hard to start, is ether sprayed into the air cleaner or direct to the carb with air cleaner off then put it back on to start.

Ralph

 

[SPYDERLK]

This time of year, and really almost any time if it really is hard to start, is ether sprayed into the air cleaner or direct to the carb with air cleaner off then put it back on to start.

Ralph

I usually just drip some gas on the air filter while cranking. It typically gets engine going immediately. And then the pulse pump fills the carb right up.

 

[jaxs]

Hopefully you solved the problem with what has been done. If it go's back to it's old ways and you are looking for an easy solution,try this. Drill a hole through filter cover so that carb cleaner/starting fluid straw will squirt directly into carb throat. You can also fill a zoom spout bottle with gas instead of using airasol sprays. Drop a machine screw in hole to prevent dirt being sucked through hole. That alow'spriming without removeing and reinstalling filter cover each start up. If you prefer learning to troubleshoot the system and willing to spend the time,we can try working through the process.

 

[WranglerX]

Hopefully you solved the problem with what has been done. If it go's back to it's old ways and you are looking for an easy solution,try this. Drill a hole through filter cover so that carb cleaner/starting fluid straw will squirt directly into carb throat. You can also fill a zoom spout bottle with gas instead of using airasol sprays. Drop a machine screw in hole to prevent dirt being sucked through hole. That alow'spriming without removeing and reinstalling filter cover each start up. If you prefer learning to troubleshoot the system and willing to spend the time,we can try working through the process.

Done that...Actually there is about a 3/32 hole there for wand of carb cleaner spray can (covered with duct tape) ....Thinking of plugging hole with something with a removable cap.... But better yet solving hard start and do away with need for any "priming"....

There Is room for something like this in air cleaner cover and under hood (threaded schrade valve stem) ....

Generic and easily done and if cap disappears I can steal one off wifes honda...

Dale

 

[jaxs]

Done that...Actually there is about a 3/32 hole there for wand of carb cleaner spray can (covered with duct tape) ....Thinking of plugging hole with something with a removable cap.... But better yet solving hard start and do away with need for any "priming"....

There Is room for something like this in air cleaner cover and under hood (threaded schrade valve stem) ....

Generic and easily done and if cap disappears I can steal one off wifes honda...

Dale

That valve should work fine,make sure soft seal is gas/oil resistant or it can really gum up the carb.
If you don't have a fuel shut off valve in line,install one because it can save lots of trouble over the coming years. I'm speaking of a manual ball valve (if you have a valve/solenoid on carb with wires leading to it,that's not a shut off,it's to prevent backfire when warm engine is shut down). Every time you put mower away turn fuel off. Not only can gas leak through carb,it can wash oil off pistons and cyl walls then dilute oil causing engine damage. After mower has been parked a day or two,,leave fuel turned off and turn engine over several times without choking and throttle 1/2 to wide open. If carb leaked while parked,that should purge residual fuel from intake and help prevent flooding while starting. Turn fuel on and attempt to start. Odds are it will still be difficult to start so it's time to look at carb. If it has a Niki carb or Niki clone,often,they are easier to replace than repair. Problem is that jets aren't staked in well and they fall out. If it is Niki and you tear it down,clean jets using same tool as in next carb jets. If carb look's like http://www.amazon.com/Briggs-Stratton-693479-Carburetor-Replaces/dp/B083LP5YM2/ref=sr_1_8?keywords=693479&qid=1579928343&s=lawn-garden&sr=1-8,you are in luck. No need to remove carb,remove 4 screws holding upper and lower halves togeather and lift top off. You can now see if carb has trash in it. Make sure atomizer tube holes are open and clean. Idle jet is recessed but easily seen when looking down into carb. The jet has screw slots but it isn't necessary to remove it. Simply use straw on cleaner to spray jet. Use a torch tip cleaner to clean jet. Be very ginger with the tip cleaner inserting the largest one that slide's in without force. Keep wire straight and parallel with jet as its drawn back and forth. Flush with cleaner and try next larger wire. If it needs more than light force to slide in,go back to first wire until the larger wire can be drawn back and forth. If you have letter bits,you can use those instead of tip cleaner but the goal is to thougerly clean idle jet plus increase it by one size. On side of carb,below choke lever is a 1/2-9/16 plug. Remove plug to access high speed jet. Don't enlarge hi speed jet,just make sure it's completely open and clean. The float needle and seat are accessiable if you want to replace them but I want to offer some advice before ordering parts. You can buy a complete kit including fuel pump for what 2 or 3 parts cost when bought individually. It's worth while bitting the bullet and paying for Briggs label on carb kits. There are many overseas manufactures turning out parts that are not resistant to additives in fuel so they melt. If you choose an ecconomey kit,soak it in fuel overnight to see if it destort's before installing it. Because you mentioned valve adjustment, I spect you have a Niki on this engine but if you come across one of thses older carns you will know how to clean it without taking carb off of engine. Increasing size of idle jet will help performance from idle through transition to cruise rpm on most carburated engines built in recent decades. I noticed you live on the left coast so don't blame me if greenies leanch you for circumventing regulations.and causing globable warming.

 

[tractorgp]

Hopefully you solved the problem with what has been done. If it go's back to it's old ways and you are looking for an easy solution,try this. Drill a hole through filter cover so that carb cleaner/starting fluid straw will squirt directly into carb throat. You can also fill a zoom spout bottle with gas instead of using airasol sprays. Drop a machine screw in hole to prevent dirt being sucked through hole. That alow'spriming without removeing and reinstalling filter cover each start up. If you prefer learning to troubleshoot the system and willing to spend the time,we can try working through the process.

This was my approach.

 

[Richard001]

Before you go off on work around's for your hard starting issues, you should make sure that your fuel shutoff solenoid is working and that the voltage is being applied when it should.

I doubt very much that Briggs developed this engine, found that it wouldn't start well when cold and said, "Ah what the ****, just sell it".

So take some time an look into the problem. Below is some pics from the manual showing how to check for the proper voltage at the solenoid.





What the manual does not suggest, but you should do this. If the voltage suggested in the test procedure comes on as indicated, you may want to check the solenoid itself. Set your meter to ohms, on the lowest ohm scale if you have that choice. Place the two meter leads on the contacts of the solenoid. (note: you may have to insert the probes into the solenoid housing to make contact) You should get some sort of reading. Perhaps from 20 to 100 ohms. If you get no reading, then the manual process is correct.

It often happens that the OFF/ON/START switch goes bad. It doesn't apply the voltage to the solenoid when it should. This can be a bit mystifying because the engine starts when warm. That happens because the engine does not need much fuel to start when warm.

It is important to note that the fuel shutoff solenoid must also be active, i.e. open when the OFF/ON/START switch is in the START position. I have seen cases where the solenoid is active in the run position of the switch, but not active during the start position of the switch.

Richard

 

[RandyT]

Before you go off on work around's for your hard starting issues, you should make sure that your fuel shutoff solenoid is working and that the voltage is being applied when it should.

I doubt very much that Briggs developed this engine, found that it wouldn't start well when cold and said, "Ah what the ****, just sell it".

So take some time an look into the problem. Below is some pics from the manual showing how to check for the proper voltage at the solenoid.

View attachment 638669

View attachment 638670

What the manual does not suggest, but you should do this. If the voltage suggested in the test procedure comes on as indicated, you may want to check the solenoid itself. Set your meter to ohms, on the lowest ohm scale if you have that choice. Place the two meter leads on the contacts of the solenoid. (note: you may have to insert the probes into the solenoid housing to make contact) You should get some sort of reading. Perhaps from 20 to 100 ohms. If you get no reading, then the manual process is correct.

It often happens that the OFF/ON/START switch goes bad. It doesn't apply the voltage to the solenoid when it should. This can be a bit mystifying because the engine starts when warm. That happens because the engine does not need much fuel to start when warm.

It is important to note that the fuel shutoff solenoid must also be active, i.e. open when the OFF/ON/START switch is in the START position. I have seen cases where the solenoid is active in the run position of the switch, but not active during the start position of the switch.

Richard

Kohler comes to mind of having that issue. Either due to key switch not compatible with new engine with fuel solenoid, or for some reason key switch looses contacts between the B+ and the L terminals

 

[Richard001]

Kohler comes to mind of having that issue. Either due to key switch not compatible with new engine with fuel solenoid, or for some reason key switch looses contacts between the B+ and the L terminals

Yep, I re-powered a friends Cub Cadet Zero turn with a Briggs engine. After getting everything hooked up, gassed up, and filled with oil, I tried to start it. Sometimes it would start the next time it would not. I'm not sure what the problem was with the switch as it worked for the original engine.

Once I figured out the problem, the shut-off solenoid was not getting voltage during the crank stage, I fixed it with a wire and a diode with one end connected to the starter and the other end wired into to original wire to the solenoid. Worked like a charm.

Richard

 

[WranglerX]

Well after machine sat for a week or so I tried to start it, and it started fine so bad vacuum pulse line to pump would seem to have been problem.... Now cheap battery is dying... Cant win...

Dale