Mower engine hot start issue

[shadetree 5,877]

7 minutes ago, jeepwm69 said:

 

I hate those things.  

yeah, i just ran into this very same thing with my mower a couple weeks ago, worhtless on there...lol

[Misterclean 421]

On 7/5/2021 at 12:51 AM, LedFTed said:

the 1st pic. is not what i wanted to post. the 2nd is... i intend to install this on the ex-mark zero turn. its out of warranty,  an i have been through plenty of solenoids with this creature. when its hot, is the worst. wont start, have to get a charger. so i got a boost to the battery an now the battery will turn the starter, to fire the motor.

i ave already tested this, with a jumper start button, just hook up 2 wires, one goes to the battery, the other goes to the solenoid. gives extra strength from the battery, more voltage, or current. i have always jumped battery voltage to the plus terminal on the solenoid, and didnt know any other way. till of late. i was afraid to use my push button  jumper, across the battery terminals at the top of the solenoid.

Check your valve lash. If it is too large it disables the automatic compression release causing problems like you mentioned.

 

[Misterclean 421]

Your can also try to clean the cooling fins and maybe slow the engine speed down 50 RPM's. Overheating causes the fuel to boil. Wrapping insulation on the fuel hoes helps too.

[_Wilson_™ 6,563]

1 hour ago, Misterclean said:

Check your valve lash. If it is too large it disables the automatic compression release causing problems like you mentioned.

 

 

thats what cured mine, she got really hard to start, after i adjust the valves she starts fine, but i have no idea that briggs 15 horse ohv had a decomp built in. 

[jeepwm69 7,599]

The little Yamaha 80 4wheeler that @basfnb's brother gave me wouldn't start.  I nosed around online and found that the intake valves on them tend to tighten up over time, and eventually they wouldn't start.

 

I adjusted valves and it fired right up.  Smoked like a diesel rolling coal, but it ran!

[slowindown 494]

On 7/4/2021 at 7:48 PM, shadetree said:

great, keep us updated !.

 

 

Well unfortunately that didn't fix it.  It did the same thing as with the old one.  With either of them, I can hold the carb solenoid and feel the electo-magnet engage and presumably pull down the plunger when I turn the key to the on position, whether the engine is hot or cold.

[_Wilson_™ 6,563]

and your original solenoid was oem ? but you also said you got a cheeper one, and the engine acted the same.... with both ? my other snapper (v-twin) acted kind of the same, and it ended being the fuel pump, it would run fine after i got it fired up it but like yours it wouldnt start warm and i always let it cool down before shutting it off, the fuel filter was spotless, i had never ran it out of gas, kept it full of sta-bil treated gas. 

[shadetree 5,877]

2 hours ago, slowindown said:

 

 

Well unfortunately that didn't fix it.  It did the same thing as with the old one.  With either of them, I can hold the carb solenoid and feel the electo-magnet engage and presumably pull down the plunger when I turn the key to the on position, whether the engine is hot or cold.

is plenty of fuel reaching the carb ?.

[slowindown 494]

2 hours ago, _Wilson_™ said:

and your original solenoid was oem ? but you also said you got a cheeper one, and the engine acted the same.... with both ? my other snapper (v-twin) acted kind of the same, and it ended being the fuel pump, it would run fine after i got it fired up it but like yours it wouldnt start warm and i always let it cool down before shutting it off, the fuel filter was spotless, i had never ran it out of gas, kept it full of sta-bil treated gas. 

Yes. Old solenoid came on it when I bought it new. It acted exactly the same with the oem solenoid and the new aftermarket one. 
 

And yes, the fuel pump is on my list to change as a possibility. Any serious work on it will have to wait until after grass season. 

[slowindown 494]

2 hours ago, shadetree said:

is plenty of fuel reaching the carb ?.

I’m not 100% sure. Amongst my first thoughts was vapor lock. 

[_Wilson_™ 6,563]

vapor lock was also what i was thinking it could be, when you changed the fuel filter, did you re route the fuel line ? or maybe left  a heat shield off ? because, it looks to me like it should hit with starting fluid..... might not run, BUT should at least hit, could be when you ran it out of fuel, it could have gotten trash in the fuel pump... is your fuel before, or after the filter ? 

[shadetree 5,877]

33 minutes ago, _Wilson_™ said:

vapor lock was also what i was thinking it could be, when you changed the fuel filter, did you re route the fuel line ? or maybe left  a heat shield off ? because, it looks to me like it should hit with starting fluid..... might not run, BUT should at least hit, could be when you ran it out of fuel, it could have gotten trash in the fuel pump... is your fuel before, or after the filter ? 

do these even have a fuel pump ?, most mowers are gravity fed, or vacuum fed. 

[shadetree 5,877]

1 hour ago, slowindown said:

I’m not 100% sure. Amongst my first thoughts was vapor lock. 

with the float bowl off, ( make sure you have an inline cut-off on fuel line ) turn cut-off on, you should see plenty of fuel pouring out from float needle ?, if not ?, then i would say the tank is not venting .

[_Wilson_™ 6,563]

yes, i believe vacum / pulse operated, mine has 3 lines in, and out, and one line that goes into the right hand valve cover, never seen a design like this before, but I'll say this, i don't like it at all! my old lt15/38 snapper is gravity fed, i never had a a single issue out it except the float valve seat which i replaced, she still runs good, but has not tell how many hours, lol, and i added an inline cut off, and gravity fed should have a fuel shut off inline from the tank to the carb. 

Edited July 13, 2021 by _Wilson_™

[LedFTed 1,127]

On 7/7/2021 at 4:52 PM, Misterclean said:

Check your valve lash. If it is too large it disables the automatic compression release causing problems like you mentioned.

 

708cc, is from china, (i didnt know that, at the time)  i already had to adjust the valves once. its overdue. may have starter issues also. the hot going to the starter looks burnt. it acted up today, i could hear it popping inside of the house. it quit before the time i got out of the house, wouldnt start back up. ya just gotta love china, dont ya.. 😬😬😬

Edited July 13, 2021 by LedFTed
needed more grimace

[Misterclean 421]

14 hours ago, LedFTed said:

708cc, is from china, (i didnt know that, at the time)  i already had to adjust the valves once. its overdue. may have starter issues also. the hot going to the starter looks burnt. it acted up today, i could hear it popping inside of the house. it quit before the time i got out of the house, wouldnt start back up. ya just gotta love china, dont ya.. 😬😬😬

Disabled compression release can burn up a starter, solenoid and wires. It''s very hard on the battery too.

 

[shadetree 5,877]

4 minutes ago, Misterclean said:

Disabled compression release can burn up a starter, solenoid and wires. It''s very hard on the battery too.

 

agreed ^^^ !.

[slowindown 494]

18 hours ago, _Wilson_™ said:

vapor lock was also what i was thinking it could be, when you changed the fuel filter, did you re route the fuel line ? or maybe left  a heat shield off ? because, it looks to me like it should hit with starting fluid..... might not run, BUT should at least hit, could be when you ran it out of fuel, it could have gotten trash in the fuel pump... is your fuel before, or after the filter ? 

 

I didn't change anything other than switch out the filter.  Nothing was rerouted.  It was doing it before I changed the filter.  It has been doing it for at least several years, maybe longer, maybe since new.  Over 1000 hours.  It won't hit on starting fluid shot or gas poured in the intake boot when it's hot.  Dump a 5 gallon bucket of water on it though and it will crank back up.  I had also originally thought coils since it's not hitting when hot - but if it's coils, why's it not shutting down when hot?  I can mow sunrise to sunset with never cutting it off...

 

I've never done anything to the engine other than fairly regularly oil/filter and air filter changes.  I changed plugs and the fuel filter for the first time last summer or the summer before.

[slowindown 494]

17 hours ago, shadetree said:

do these even have a fuel pump ?, most mowers are gravity fed, or vacuum fed. 

This is a pic of the fuel pump on mine:

 

 

[_Wilson_™ 6,563]

yep, that's the critter my v-twin has ^^^^ 

[slowindown 494]

I won't have much time for serious diagnostics until after summer but before I mow this weekend I'm going to take the shouds off and make sure the cooling fins are not overly clogged up with grass and such.

Edited July 13, 2021 by slowindown

[_Wilson_™ 6,563]

and no sign of rodent damage (wires being chewed on ?) 

[_Wilson_™ 6,563]

and we just missed @Misterclean he helped me with a weed eater carb issue, back a few years ago, still runs like a top! he would be the one I'd talk to. 

[slowindown 494]

13 minutes ago, _Wilson_™ said:

and no sign of rodent damage (wires being chewed on ?) 

Nope

[_Wilson_™ 6,563]

well, this one has me baffled, okay without going back, this started, and over the years and got worse over time ?