Hi. I need some advise on my 1974 Johnson 70hp. I hadn't used my boat in 5 years (I have a 4 year old daughter - hmmmm corelation?) and I want to get it back out on the lake.
I had left the gas in the carbs and lines 5 years ago - bad idea. I totally cleaned out the carbs and rebuilt them. It was pretty easy I thought. Anyways it starts up and runs great now!
I also rebuilt the water pump because even when I owned it and was using it almost every weekend, I had never rebuilt it so I figured it was time.
I thought I got it all correct but am I paranoid that it is not pumping. I'm afraid I did something stupid like letting the woodruff key slip out or something.
From what I can tell this engine does NOT have a tell-tale hole. At least with muffs on I don't see water coming out of any holes. I've read conflicting things on the internet, and none of my shop manuals specifically say. And I don't remember if I saw one 5 years ago or not on this model.
I saw the sticky post about adding one, or threads about adding a water pressure gauge - I'm afraid mods like that are a little more than I am comfortable with.
What are my other options for knowing that it is cooling?
I did ground out the temp sensor to see if the overheat buzzer sounds at the shifter, and it did buzz. I dont know if I can rely on that temp sensor doing its job though. How do I know it will detect the correct temp? Should I just hope for the best and run it and see if it goes off?
Can I shoot one of those laser temperature devices to measure the exterior temperature of the water cooling jacket to see how hot it gets? What would be an acceptable temperature. After idling for a bit with muffs it was MUCH too hot for me to leave my hand on it so I shut the engine back down right away to prevent damage.
I guess I can take the lower unit back off and look at the water pump to make sure the impeller is spinning and the key is on. I used gasket sealer though so I'm not sure what I will have to do if I take it apart - if I will need new gaskets again.
Do I need to submerge it in water (as opposed to the muffs) and rev it up? Will I see water spit out the 2 holes (that I thought were exhaust holes) on the back of the engine? I can submit a picture of them if it helps.
What about a thermostat? Does this model have one and should I check it for functionality?
Please give me some advise on how I can be sure its doing its job.
Thank you very much!