1978 Johnson 2hp Pumping water ? and fuel question

[Putzaroni1]

I purchased a very clean 1978 2 hp Johnson 2R78R that has nostalgic value to me because I remember my Dad replacing our old Evinrude 60 with a 1978 Johnson 115. It was an awesome motor.

Anyhow, I just pulled it out from winter storage and put it in a bucket of water to give it a good run. I changed out the impeller and replaced the gear oil first. The impeller was end of life for sure and the old gear oil was ugly (marbled with dark and clearish). It's all clean and lubed up now.

My 2 questions are.

1) How can you tell if the motor is pumping water ? There is no telltale like on larger kickers. I see the 4 holes at the back that are exhaust. A little bit of water comes out of those but no where near enough to cool the motor. I ran the motor for 10 mins at 3/4 throttle and it didn't get too hot. I would just feel better if I knew how to tell.

2) The motor probably needs a really good run but I ran it at about 1/2 throttle to 3/4's with a couple bursts to full but it sputtered a fair bit and didn't run anywhere near as smooth as it did when I saw it run before I bought it.
I drained the fuel out of it before storing it but didn't fog it (will next time for sure). I also sprayed Carb cleaner at the carb while it was running and it would almost die and then rev back up. Does that mean there is an air leak ?

Does it sound like the carb just needs to be pulled off and cleaned properly ? I ordered the service manual off of EBay but it won't be here for a week and I'm getting impatient as this is going to be my personal fishing craft and fly fishing season is here.

Any suggestions or answers would be much appreciated.......

 

[vendingworks]

Re: 1978 Johnson 2hp Pumping water ? and fuel question

I have a 2R75 and if your getting spray, it`s cooling great.
Question 2 When you say running rough, you mean it is 4stroking or missing? You have a high speed and low speed adjustment on the front of engine. When trolling adj the low speed to a smooth sound, the high speed adj for same smooth run at a more rich setting. should be very close to center settings.Play with them and see if it helps.

the motor will try to stall normally when you spray into the carb,takes the air away.

Hope this helps you great little motors!

 

[Putzaroni1]

Re: 1978 Johnson 2hp Pumping water ? and fuel question

Update:
So I discovered that if I pull the choke half way out it tends to run just fine. I tried all the way out and it would die or all the way in and it would die. I did some more research and discovered that this is likely due to a dirty carb (even though I drained it for winter).
I pulled it all apart tonight, took the slow and high speed needles out, dropped the bowl and sprayed everything I could see out with Carb Cleaner. I thought I'd try this and if that doesn't work we do the full rebuild. I got it all back together and fired it up. It took a bit to get it to start but once it did it needed a bit of choke at first but after about a minute it seemed to be running great at both low and high speed. I will take it out on the lake and put it through it's paces on the weekend. You guys are awesome. I never would have tried this myself !

One final question. What is a Throttle detent spring ? It has one on the right side if I'm looking a the motor and I didn't know what to do with it and can't find anything that says what it's for or how it should be positioned ! Thanks again and if you know, please let me know.