Yamaha 4HP outboard - cannot pull starter cord - jammed.

Hey Pete.. this sounds serious.... will it rev up while in neutral? If it revs freely and high.. the power head should be ok.. if it will NOT rev up freely and high.. STOP - you are causing more damage..
Check the compression with a good gauge..it should be 125psi minimum.. with no more than 10 psi difference between any two cylinders.. DO this WITH the THROTTLE WIDE OPEN...
Can you turn the propeller by hand while it is in neutral?..Of not.. this is the problem.
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Where do you connect the 12 v battery power cable to the engine on a 4stroke 40 hp yamaha year 2005.

Hello,

Mariner 4hp are identical to Yamaha engines.
You should find a sticker on the port bracket with serial and model number.
If that sticker has disappeard, an aluminum piece is stamped in the side of the cilinder. The numbervstamped in that round pieceis the serial number. I can convert that serial number in a year/model number...

First, check the linkage under the motor cover. It stoops you from given the engine too much throttle when the motor is in neutral but can jam the system if you try to shift out of gear at too fast of speed. Or a link in that system could be broken/loose. If all looks OK the check your lower unit oil. If none or water, the gear case could be trash.

sounds like you need to find the shift rod. It will be behind a plate on the exhaust housing or under the carb.

Pull starter rope wheel is Jamming against casing usually some lube n check for ware will fix it

Check the starter motor on the bench clamped in a vice ,you may have sluggish or worn brushes .

Open the fuel valve ( at the back near the spark plugs).
Pull the choke knob ( SB side at the lower front of the motor)
Set the throttle handle in 'start' position ( abour 1/4 of the travelling way from SB to Port)
Pull the rope starter.
Should start easily.

you have a short or another wiring problem