1968 Johnson 40hp lower unit moves forward and backwards....

[CptDuke]

I just got a 1968 40hp Johnson outboard. I was checking it out and noticed that:<br /><br />1. The lower unit actually moves forward and backwards about a 1/2 inch.. Any suggestions?<br /><br />2. Motor starts up great, but didn't have a tell tail water supply, where does the water exit on this motor? Water pump?<br /><br />Thanks,<br />Duke

 

[CptDuke]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

Any suggestions?

 

[lark2004]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

is this a manual shift or electric shift gearcase?

 

[umblecumbuz]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

Hi Duke,<br /><br />When you say the lower unit moves forwards and backwards a half inch - do you mean it moves even when you hold the motor still? ie. - it's loose on the upper unit?<br /><br />Or do you mean the whole unit can be moved while it's bolted to the transom?

 

[CptDuke]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

How can I tell whether it is manual or electric shift. It is cable operated from the lever to the engine.<br /><br />When I say "lower unit moves 1/2 inch," i mean that the upper unit does not move. The lower unit that constains the water pick-up and below moves separately from the upper unit. <br /><br />Thanks <br />Duke

 

[Goodoleboy]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

Duke.....Every bolt in that lower unit has to be missing, or worse yet broken off.<br /><br />Good Luck!

 

[Chris1956]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

Duke, There may be rubber motor mounts between the outer casing of the midsection, and the inner casing. Check to see that they are intact.

 

[CATransplant]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

OK, it's manual shift, then. If the lower unit, as you describe it, is moving, then it's in a world of hurt. It's held on by several bolts, and can't move if they're secured. If the bolts look tight, and it's moving, I'm guessing there some money about to be spent.<br /><br />Let's define this really closely, though. You can see the bolts holding the gearcase, complete with the water pickup screens, etc., right? There's a joint in the lower section right above the part where the bolts go in. Is that where the movement is?<br /><br />On that outboard, there is an outer housing, as well, just above that point on the lower unit. It has rubber mounts and a rubber seal between it and the inner housing.. If the movement is between the inner part of the lower unit and this outer cover. If those are missing or worn, you can have some movement between the inner and outer lower unit housings.<br /><br />I suspect that's what's going on here. The movement will not be at the actual seam where the gearcase attaches to the inner housing, but, instead, between the inner housing/gearcase, and the outer housing, which is there for soundproofing purposes.

 

[CptDuke]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

CATransplant,<br />The movement IS between the inner part of the lower unit and the outer cover.--Is that designed for soundproofing as you say? How much movement is normal before replacement of those mounts and seal? <br />Thanks again,<br />Duke

 

[krb113]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

Just for the fun of it all, check and see if the movement is from the "pivot bushings" (from lack of actual part description)where the actual pivoting of the motor to the transom mount is. I have an 18 hp Johnny that have the bottom one worn out and it moves at least a 1/4" all around and will give a "pop" sound on the boat when you give it a takeoff with WFO throttle.

 

[CATransplant]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

CptDuke,<br /><br />I went out and checked my '58, which has the same outer housing. There was no movement at all between the outer and inner housing.<br /><br />I suspect that the rubber mount at the bottom is either missing or perished. <br /><br />And yes, the outer housing has no function other than soundproofing. However, it's pretty much impossible to eliminate, I'm afraid.<br /><br />Most of those rubber mounts are still available, although I do not know how long that will be the case.<br /><br />It's a dilemma. I don't think any harm will come to your outboard, but it might well be worth removing the rear cover (several screws) and have a look at the rubber mounts.<br /><br />You can see an exploded view of this at ishopmarine.com. Click "parts lists" at the top of the page, then drill down to your model. You'll see the mounts in the "lower unit group" illustration.<br /><br />I suspect that something could be bodged up to replace an unavailable mount.

 

[CptDuke]

Re: 1968 Johnson 40hp lower unit moves forward and backwards....

I really appreciate everyones help,<br />Thanks again...<br />Duke