Will only cold start with starting fluid

[JRess 12]

My son has a 310-8 that used to start with no problem. Now if cold will only start with a spray of fluid. If warm starts right up. What steps should I be taking to troubleshoot this?  Thanks all. John. 

[OutdoorEnvy 1,522]

Offhand check that the choke is functioning properly.  Sometimes the cable can get off a little or need adjustment.  Verify the choke butterfly fully closes with choke on, and of course full opens when off.  Other than that a dirty/malfunctioning carb is likely the issue.

[peter lena 8,634]

 

 

 

 

 

 

 

 

 

 

 

 

@JRess   agree with  @OutdoorEnvy   on the basic functional check and , carb bowl check , erratic related starting / running issues , go hand in hand with dirty carbs. that entire related fuel system is probably due for a total look / see. pete   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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[Ed Kennell 38,209]

Install a marine primer bulb in the fuel line.     The fuel pump is probably losing it's prime.       A couple squeezes will prime the fuel pump and carb making for an easy start.

[WHX?? 48,828]

Yep check the choke, air filter & a carb cleaning. Maybe run a little seafoam through her.

[953 nut 55,294]

One of the most common causes of fuel system problems is E-10 Ethanol added gas. There have been lots of threads on here about the problems E-10 can cause. I would suggest that you only use non ethanol gas in any small engine. Adding some Seafoam as @WHX?? suggested is a great help too.

To find a station that sells non ethanol gas use this site.   https://www.pure-gas.org/

[WHX?? 48,828]

Not a question for finding non-e gas around here Richard..... it's paying for it! 

[Darb1964 1,043]

Definitely want to get away from using any either product, much great advice. 

[Rick3478 428]

Fuel pump may be getting worn out.  When the valves get leaky, fuel all drains back into the tank when it sits, then have to crank a long time to pump it back up to the carb.  Or with starting fluid, once you have it running the pump works much faster.  Inline priming bulb might work for you, or some folks like an inline electric pump.

[SylvanLakeWH 25,597]

1 hour ago, Ed Kennell said:

Install a marine primer bulb in the fuel line.     The fuel pump is probably losing it's prime.       A couple squeezes will prime the fuel pump and carb making for an easy start.

 

Have that on my C 105. Works great!!!

 

Edited July 8, 2022 by SylvanLakeWH

[ri702bill 8,327]

Be carefull with the ether - it has NO lubricity - a lot of folks here use a short blast of carb cleaner - but, as described above, that is a Band-Aid fix to the real issue - remember, it ran just fine when it was made....

[davem1111 2,030]

1 hour ago, Rick3478 said:

Fuel pump may be getting worn out.  When the valves get leaky, fuel all drains back into the tank when it sits, then have to crank a long time to pump it back up to the carb.  Or with starting fluid, once you have it running the pump works much faster.  Inline priming bulb might work for you, or some folks like an inline electric pump.

 

I've had 2 original fuel pumps fail in the last 2 years.  One on a 312-A Kohler and one on a 416-8 Onan.  Replaced them both with Carbole 12v pumps, and I am quite happy with them.  You have to either 1) add an on/off switch for the pump or 2) wire it in somewhere to come on when the key is on and off when off, but that's not much of a challenge. I used method 1 as a quick fix when first installed, then rewired to method 2 when I had more time to tinker.  Also using clear filters (and some guys use clear fuel lines - I haven't done this on anything yet) so you can see the gas flow makes troubleshooting a lot easier.

[gwest_ca-(File Mod) 11,046]

A safe starting fluid for our small gas engines is WD-40. The propellant is propane with the oil providing some lubrication.

Either should only be used on some of the diesel engines - not those with glow plugs.

[JRess 12]

Thanks all.  Did pull the carb and the bowl was bone dry.  I appreciate the pic of the marine primer and think I will go in that direction if cleaning the carb doesn't work.  Adding an electric pump is probably above my comfort level.  I will let all know how it works out.

[davem1111 2,030]

44 minutes ago, JRess said:

Thanks all.  Did pull the carb and the bowl was bone dry.  I appreciate the pic of the marine primer and think I will go in that direction if cleaning the carb doesn't work.  Adding an electric pump is probably above my comfort level.  I will let all know how it works out.

 

If you end up needing to do the fuel pump replacement, it's not very difficult. Here is a picture of one I did. Not the most optimal or attractive location, but it works. You might need to buy some 1/4" fuel line depending on how you re-route the lines. Good idea to replace the lines all the way to the tank, filter(s) (I put one back near the tank and another up front), and maybe the shutoff valve & grommet at the tank while you're at it. I don't remember if you said you were getting fuel through the line all the way to the carb, but I've seen shutoff valves go bad and not open too...