How do can you roll start a 86 samurai - 1986 Suzuki Samurai

Syam, Carbureted Suzuki Samurai is 4 to 4.5 psi.
1.3L 8V and 1.0L 6V TBI
Key on: 22.7 - 29.9psi
Idling: 12.8 - 20.0psi.

Samurai and Sidekick TBI
Key on: 34.1 - 39.8psi
Idling: 24.2 - 29.9psi

Sidekick MPI
Key on: 35.6 - 42.7psi
Idling: 29.8 - 37.0psi

Swift DOHC MPI
Key on: 35.5-38.4psi
Idling: 25.6-29.9psi
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TeamSwift View topic fuel pressure looking for 38 45 PSI
http://blog.lowrangeoffroad.com/wp-content/uploads/instructions/instructions/86-89-Suzuki-Samurai-1.3L-Fuel-Pump-Pressure-Test.pdf
Fuel pump testing

Check the drive shaft first, ok, then the input shaft or main shaft inside the ****** is broken.

Sounds like the timing belt has broke but without a look ? head under the bonnet and kick up the exhaust i honestly couldnt say please ask a local mechanic to have a look for you

the battery is in the trunk under the carpet on the passenger side closest to the bumper

I had a similar issue with my '86....driving home, made a left turn, and engine shut down. Coasted to a stop, and had a look under the hood. Cranked over fine, had gas, spark, but no go! After a tow home, and more in-depth investigating, turned out that the timing belt had broken! The older engine has no interference between valves and pistons, so installing a new belt got 'er going again for about $40. You can look down though the oil fill port or loosen the upper screws on the belt cover to confirm that the valves are/are not moving when the engine cranks.
mr_haney2u

yes

check float level

go to acks facts 4x4 suzuki forum vacuum diagram

The samurai tranny shifter's wear down and the shift pin tends to break cause slop in the shifter and making it harder to get into 5th gear.

It sounds more like a timing problem. If it backfires through the carb that means the intake valve is open when the spark plug fires. Same with the exaust but it the exhaust valve that is open.