312-8 needs to be "primed" every time

[fish59 0]

Thanks to all of you in the past who have given me advice. Here's my latest: I need to squirt gas into the carb every time I start her cold. Its time consuming removing the air filter to do this. Is this caused by a bad fuel pump? Once started, she runs fine. Thanks in advance for your advice.

Rick

[Goldnboy 1,030]

Quite possible need to replace fuel lines..when they age the rubber become brittle and hard 

[Ed Kennell 41,943]

Add a marine primer bulb at a low spot in the fuel line.   Two or three squeezes and you'll have instant starts.   Your battery and starter will thank you.

[ri702bill 9,406]

5 hours ago, fish59 said:

Is this caused by a bad fuel pump?

Not so much bad, but dirty. The little valve discs can get crud under them. If that happens, fuel can drain back. I added a primer bulb on my C81 - no regrets.

One other choice is to go with a low pressure electric fuel pump.

[SylvanLakeWH 28,392]

6 hours ago, Ed Kennell said:

Add a marine primer bulb at a low spot in the fuel line.   Two or three squeezes and you'll have instant starts.   Your battery and starter will thank you.

[953 nut 59,918]

Time for a bit of deferred maintenance to be done. As @Goldnboy mentioned, fuel hose could be old and degraded restricting fuel flow. Also the fuel pump valves could be leaking as @ri702bill suggested. A new fuel hose, filter and pump cleaning or replacement should get the job done.

If you have been using gas with ethanol STOP.  Ethanol will ruin fuel system components on small engines. To find a station that sells real gas use this site,   https://www.pure-gas.org/

[rmaynard 16,293]

Might want to put a check valve between the fuel pump and the fuel tank. That way, any gas that may siphon back towards the tank due to a weak fuel pump, will be held by the check valve.

 

[clueless 3,233]

10 hours ago, Ed Kennell said:

Add a marine primer bulb at a low spot in the fuel line.   Two or three squeezes and you'll have instant starts.   Your battery and starter will thank you.

Do this first, it will cost you about $15, if it's still not starting then go from there. Even if this doesn't fix the problem you've made it to where it will start up four time faster than it use to once you've fix your problem. Best $12 to $15 improvement I've ever made on my rear tank tractors

[peter lena 9,262]

@fish59 another area you can check is the function of the choke linkage and the throttle plate , very often just a small tweak  and some  penetrating oil makes  parts move easily , often refer to smooth easy function of  parts . choke is smooth and easy , pete 

[ri702bill 9,406]

As I mentioned earlier, I added a Marine primer Bulb on the C81. I got ambitious and mounted it under the seat pan with a spring loaded rod & knob under the seat. Had all the materials in house, why not.....

 

 

Edited Thursday at 05:34 PM by ri702bill

[Ed Kennell 41,943]

Luv it, a bouncy seat powered fuel pump.

 

 

[Handy Don 14,061]

9 minutes ago, Ed Kennell said:

Luv it, a bouncy seat powered fuel pump.

Does it hit the seat? I think Bill just lifts the seat and pushes the knob a couple of times. 

[Ed Kennell 41,943]

11 minutes ago, Handy Don said:

I think Bill just lifts the seat and pushes the knob

                                            But R Goldberg would surely have made it seat activated.    

[SylvanLakeWH 28,392]

That is cool!!! 

[ri702bill 9,406]

Nope - purposely designed not to hit the underside of the seat. As @Handy Don said, flip up the seat, give it a couple of pushes, lower the seat, start it up.

I did this to "protect" the fuel line & primer. Seen way too may installed out in the open just a-waitin' to get snagged on something....

[ri702bill 9,406]

23 minutes ago, Ed Kennell said:

                                            But R Goldberg would surely have made it seat activated.    

Rube would have used gears, twine, and a mousetrap....

[ri702bill 9,406]

52 minutes ago, Ed Kennell said:

Luv it, a bouncy seat powered fuel pump.

Not to be confused with Archimedes in the bathtub with the fat chick......

[Ed Kennell 41,943]

My primer bulbs are located near my left foot where I have to bend down.   Now Bill has me thinking how nice a foot operated bulb would be.

[Handy Don 14,061]

2 hours ago, Ed Kennell said:

My primer bulbs are located near my left foot where I have to bend down.   Now Bill has me thinking how nice a foot operated bulb would be.

One of my Dad’s cars from the 50’s had a foot operated pump for the windshield washer fluid right next to the headlight dimmer pedal. The car was a hand-me-down from his rich uncle and aunt so it had all the options. Automatic transmission, fender skirts, an exterior windshield visor, heat, and even a radio!

[adsm08 3,233]

6 hours ago, Ed Kennell said:

                                            But R Goldberg would surely have made it seat activated.    

 

Given the location of the tank in a 312 that's a lot more sensible than it should be.

[John c 93]

[peter lena 9,262]

@ri702bill   those seat springs are easy , have them on 3 horses . once you start  experimenting , you just  keep gaining  , also like  adding a vibration pad  , as a height spacer . pete

[8ntruck 7,833]

On 7/24/2025 at 1:44 PM, ri702bill said:

Not to be confused with Archimedes in the bathtub with the fat chick......

WHAT a visual!!!