1977 Johnson 70 water pump confusion

[Cherokee-Runabout]

Today I stated to replace the impeller on my Johnson 70. I purchased the only kit that I found on iboats.com, I believe that it was Sierra 18-3388. Anyhow while removing the w/p housing from the gear case just the housing came up without the impeller. When I was sold the motor the inspection form had stated that the motor ran hot and the tell tale was weak (Could this be in part due to the key being out or would the impeller spin at all if the key had somehow popped out? Or did it pop out without me noticing when I raised the housing.).

All of that aside I set back on the task of putting the new plates,gaskets,impeller, and key back onto the shaft. The key from the old impeller was round while the new key is a half moon. The new key seems to be thicker than the old. After debating whether or not the groove in the new impeller was deeper than that of the old I decided to try it. After about 30 minutes of trying to get the key in place I decided to call it a night and check here. Has anyone else done one of these with a kit from this site? Also the older impeller was a tighter fit on the shaft than the new. I will upload some pictures tomorrow. Thanks for looking.

 

[Cherokee-Runabout]

Re: 1977 Johnson 70 water pump confusion

Well I may have solved it, I'll check over my title and make sure the year is correct, but my kit looks more like the '79 model. I'm beginning to wonder if some paper work got screwed up. I need to check the serial and model I suppose.

Update: Model is 70 Johnson EL77s, so what I'm beginning to suspect is that a '79 or later gear case was installed on this motor at some point. Are the g/c's compatible? I'm going to order the newer pump kit and see what happens. Also I suppose I should check out the return policy, not a good idea to order a part then put off replacing it.

2nd update: Stopped by the closest certified Johnson shop had the guys check out my impeller. They were hesitant to do so, told me they charged $100 labor per and that I'd be charged a consultation fee to tell me. So I went ahead and had them check it out. Turns out that the gear case was from an '81. They had a kit on hand for $80, I purchased the kit and was not charged a consultation fee. I hope that this may help someone out.

 

[Cherokee-Runabout]

Re: 1977 Johnson 70 water pump confusion

Replaced the housing, plates, impeller, and seals. Seems to be working great.