I have a 5hp Nissan outboard that lacks power. When not in gear, it will roar with power. When I shiift into gear, it lacks power. As we are cruising along, it will speed up some or slow down. I am using it on an inflatable dinghy carrying two people. I know that in gear any motor will run with less power than in gear but this is a LOT less. The motor is 15 to 20 years old and probably a little dirty inside.
Is there any gas treatment I can add to clean the engine or give it a little more power? Can I use higher octane gas (92) with oil added? Will that help?
Thanks for the advice.
Dissolving propellers: I purchased a Nissan "Sailpro" in February: 5 months ago. While painting my boat (a Pearson Ariel), I had no choice but to leave it in the water. In six weeks of immersion in sea water, the prop nearly dissolved. The paint was gone, and the leading edges of the blades were reduced to a powdery state that you could rub off with your fingers. The zinc was partly eroded - but still about 75% intact. What I found was the hub nut was finger loose - the prop was being held on by the splines and the cotter pin. The zinc isn't on the prop, and if there isn't adequate electrical continuity between the prop and the zinc, the zinc won't protect the electrically-unbonded propeller.
To their credit, Nissan support sent me a replacement prop, which has yet to show corrosion after I installed it and applied a reasonable amount of torque to the hub nut. You might want to look at your prop....
Failed starter pull cords: Sailing into the harbor one particularly windy day, I followed my usual procedure of keeping my sails active until I was sure I'd get into the harbor. I'm a commercial airplane pilot, and one of the first lessons any good flight instructor teaches is: "never trust an engine." With my slip in sight, I entered the few moments where an engine failure would be especially hazardous (pilings downwind, no room to set an anchor scope, wind directly off my bow) and I pulled down sail in the luff. Just as I got my main down... the engine died. I just shrugged because the idle was a little low and all it took was one pull to restart the engine. So... I reached back and gave the handle a pull --- and it came off in my hand -- while I watched the pull cord go ZING! back into the the engine case. With no propulsion, a 20 knot wind, 15 foot high concrete pilings one boat length away, and little steerage, I watched horrified as my bow turned 180 degrees and the boat headed straight for the stern of the San Mateo County Sheriff's motorboat in it's slip. Poseidon took pity on me and guided my boat into two concrete pilings, and after my boat played pinball with the concrete and made loud scraping sounds, landed me in the only vacant slip with nothing more than ugly black streaks on my hull.
I opened the pull handle by removing the metal insert in its center and found one inch of the severed pull cord inside, tied with a half hitch. The other side of the metal insert (facing the engine) had a stamped hole through which the cord passed, which has a metal edge as sharp as a knife! You could cut your fingers on it! The other end of the pull cord (once I got it out of the engine) had all the strands cut and splayed such that it was obvious a few strands were cut each time the cord was pulled. And since the pull cord handle conceals the back end of the metal insert, there was no way to detect the failure by inspecting it - without completely disassembling the handle. LOOK INSIDE YOUR PULL HANDLE! Pry the metal insert out and check the condition of the pull cord as it passes through the hole. I estimate that I have only pulled that cord about 50 times since I bought the engine.
My retrofit: 1) Buy one short piece of wooden dowel about one inch in diameter. 2) Cut it about four inches long. 3) Drill a hole in the center. 4) Pass the pull cord through the hole and tie a proper stopper knot. Cost: one dollar. I can now visually inspect the cord's condition.
I called Nissan Support and reported the problem. They said it's unlikely that Nissan will ever fix the defect. I reported it as well to my dealer, who said it's Nissan's problem.
Never trust an engine!