Merc 4 HP lower unit shift linkage

[GuyMN]

The other day I picked up a nice running 4 hp Merc. Mid 70's(S/N 5589319). Two cylinder with forward/Netural Shift.<br />There previous own replaced the impeller and re-assembled, But stuck in forward.<br />I went to the local library and got a service manual, but still can't get it to shift gears. The shift linkage comes out of the lower unit when you split it. It is one continuous rod from the shift lever down into the lower unit.<br />If anyone has any hint's please help.<br />Thanks

 

[zodiaccaptianjj]

Re: Merc 4 HP lower unit shift linkage

Theres a shifht shaft on the lower unit thas about three inches long. Get a pair of pliers and turn it diferent ways to see what position is what gear. Turn the shaft to a position and spin the prop. if it spins freely both ways turn the shaft again and if the prop is locked one way but spins and ticks the other its in forward. ok now put the shift lever in foward. now ut the lower unit back on like you always would and make sure verything is lined up and when you have it tightened down shift and see if it works.

 

[Chinewalker]

Re: Merc 4 HP lower unit shift linkage

Hi Guy,<br /> Zodiac has his motors mixed up. Your motor has a spring-loaded neutral clutch on the 2-part propshaft. The shift rod slides down into the gearcase and the tip will engage the spring when slid down. This spring engagement loosens the spring on the shaft and frees the drive-gear end of the propshaft from the prop-end, allowing neutral. When the spring is not engaged by the shift shaft it is running in gear - sort of a fail-safe. The tip of that shift rod can wear over time, to the point where it won't hit the spring correctly. You can pull the gearcase apart with it still on the motor, removing the rear carrier of the lower unit. That will allow you to see if the shift rod is engaging the spring or not and you might be able to tweak it a bit so that it will. It's really quite a simple set-up and should be covered in your manual...<br />- Scott