1973 18hp evinrude slipping out of gear.

I had water in my lower unit so I did all the seals and a new impeller and water pump kit.

Took her out on the water and it kept jumping out of gear into neutral while accelerating.

Everything i had read points to worn gears but I thought they looked good but I also didnt examine every inch of them. But I did notice they looked clean and not beat up. i wish i had looked closer.

Does anyone have any ideas as to what else could be causing this? When it jumps into neutral its rev really high and I had to quickly turn tiller down to slow.

Re: 1973 18hp evinrude slipping out of gear.

Sorry, but it's the clutch dog and possibly forward gear. Worn out. Older motors will jump out of gear and instantly back into gear with a bang. Yours has a detented clutch dog so if it goes to neutral, it stays in neutral----as you have found out.

EDIT: That is assuming you did the job right and got the screw in the notch in the shift rod.

Re: 1973 18hp evinrude slipping out of gear.

with F_R's thought, if it wasn't jumping before you did the work, recheck that the notch in the shift rod is up well into the brass connector before you put the screw in

Re: 1973 18hp evinrude slipping out of gear.

well I did have issues getting the notch on the shift rod into the brass housing. I sanded it clean and removed all carbon but the brass fitting was very tight still. I thought I did it properly. I will recheck it. and drop the gearcase again as well. get a better look at the gears themselves.
I will mention that if i spin the propeller by hand a little bit the lever drops into Fwd and Reverse all the way but it tends to get out of alignment a bit and not sit as far down on the mechanism below the power head that moves when u switch gears.

does this playin the propeller shaft mean hte gears could be out of alignment a bit?

Re: 1973 18hp evinrude slipping out of gear.

it's ok to spread that brass coupler open a little to get the lower shift rod in..it'll tighen around it when you tighten the connector screw..I'd suggest to you to leave the oval window off and watch the connector as you shift from fnr...may be a 2 person deal with one pulling the starter rope while the other shifts and watches..removing the spark plugs or disabling the ignition is a must as you don't want it to start..removing the plugs also makes it much easier to pull through...if you're getting f-n-r there, try testing it in a barrel before doing a lake or river test..if it's still jumping then, it seems you may well have to go back into the gercase

Re: 1973 18hp evinrude slipping out of gear.

AlTn said:

it's ok to spread that brass coupler open a little to get the lower shift rod in..it'll tighen around it when you tighten the connector screw..I'd suggest to you to leave the oval window off and watch the connector as you shift from fnr...may be a 2 person deal with one pulling the starter rope while the other shifts and watches..removing the spark plugs or disabling the ignition is a must as you don't want it to start..removing the plugs also makes it much easier to pull through...if you're getting f-n-r there, try testing it in a barrel before doing a lake or river test..if it's still jumping then, it seems you may well have to go back into the gercase

Click to expand...

Well I pulled the gearcase apart and checked all the gears and the detent balls and inspected the whole assembly. A friend of mine was there and we both think the gears look good. If we are talking worn out in minuscule properties like thousands of an inch then theres a possibility it's worn. But all 3 gears look quite good.

The shift rod is in the right spot on the brass fitting as i took that apart again as well. I'm going to try it on the lake again today. If the problem still exists i'm either wrong about the gears or another issue exists.

spun hub? driveshaft slipping? i dunno where to look next...but i'll postthe results of my test drive later this weekend.

thanks for giving me input...

Re: 1973 18hp evinrude slipping out of gear.

WEll when we reassembled the gear case we turned the clutch dog around due to a tiny bit of wear on it. and during the test run yesterday the engine performed really well. When approaching WOT it does seem to feel like its spinning out or hesitating but its no longer kicking out of gear. The hesitation im feeling almost feels like cavitation but I'm a new boater so I cant tell if its just cavitating or struggling.

All in all Im happy it ran really good compared to before. I will keep fine tuning slow and fast idle as she dies out in slow still but it was a huge improvement from before.