I love your videos! I would like to see what you do to get these motors running so good. I have a 1970’s Mercury 7.5 hp thunderbolt that I recently purchased for cheap off of craigslist. I don’t know the last time it was ran but it has good compression. What is the process you go through to get these old motors running? Would you be able to make a video on how to approach cleaning and working on these motors?
Thank you. Yes, I am thinking to start making videos of the process of cleaning and adjusting small boat motors. Please subscribe so you can get notified when I post new videos .
To get an old unused motor running again do these few steps. Firstly note how all the mechanical settings were set , timing and carb links etc and keep as reference if you don't have manual. Check compression first or all the other work might be in vain. Remove and clean the carbs. Check gear case fluid for signs of water and replace seals if necessary. Top up with new oil as you don't know where the level is any way and check condition of water pump impeller. Check condition of fuel filters. Check for good spark and replace the spark plugs. When priming the carbs check for fuel leaks at the pipes and connections. In other words just do a decent service. If the engine is seized up it could be a seized gear case. Remove the gearcase and check which one it is. I hope these tips help you out. Good luck with your 7.5 Mercury.
Can’t remember exactly if 20 hp carb has different turn out than 35 HP I am working on lately. Try one and quarter like for 35 hp. If it doesn’t start go out another quarter try it all the way up to two and half. If it doesn’t start at all there is different problem. Sorry I can’t help you with exact number, after working on so many different motors everything gets mixed up.
But it was most likely Mercury 25 HP two stroke. They are more powerful then rest of the pack. But that is only my opinion, doing this for only 7 years.
But that may be true with 2 cylinders motors. For moment I forgot about 3 cylinders 25s. Once I had Suzuki 25 HP 3 cylinder and I remember going 34 mph on empty 1448 Jon boat. Can’t say which one from 3 cylinders is faster Suzuki or Yamaha.
