1979 Evinrude 70 Hp Manual
Hello, I'm new to boating and need help with a 1979 - 70 hp Johnson. We bought it knowing we will need to correct a few things. Replaced wrong starter selonid and spark plugs. Took the boat out for the first time and it ran perfect for the first 40 minutes, then lost all power to the motor - the motor was still running, but would not rev up and would only move slow.
Engine ran smooth how ever noticed that the techometer stopped working.(Electrical issues?) We were able to restart the boat at the dock(did not notice the tech this time) After getting the boat home - we were able to restart it and now the tech worked! Not sure what is causing this - could this be a bad coil? Did the spark plugs go bad! Carburator issues. Where to start! Any and all suggestions would be greatly appreciated!
Thank you, Eric O. Re: 1979 - 70 hp Johnson - HELP!!!! Thanks for the response - the primer bulb was not collapsed. Sorry I forgot to mention I replaced the gas line with a brand new line for Johnson motors. I will be removing the plugs tomorrow and can check for spark. I have a feeling that one of the plugs died or there is an electrical issue.
Why would the tech stop working when I had the problem and then start working again? Going to go through all the wiring on the boat to make sure this is not an issue as well. It ran perfect for awhile - I opened it up throttle and started to have the problem. There was multiple plugs in the glove box. If new plugs correct the problem - should I install hotter plugs? Re: 1979 - 70 hp Johnson - HELP!!!!
Stick with the recommended Champion plugs. The electronics of the ignition system were designed as a complete system. Start changing even the spark plugs and you could imbalance something that has been fine for years. If the tach quits I would check all the screw terminals at the block on the starboard side of the motor. Corrosion or looseness can cause loss of signal. The ignition is from a different source though it too goes through the terminal strip.
Since your problem sounds like it has to do with heat I would suspect the Power Pack or the wires from the Stator/timer base to the Power Pack. Your shop manual will have test procedures for the power pack and ohm tests to run on the timer and wiring. You need a shop manual at this point. Welcome to IBoats forum, we are all here to have a good time boating.
1979 Evinrude 70 HP 70973 This 70 horsepower Evinrude outboard, manufactured in 1979, is a saltwater model. The engine weight is recorded at 230 lbs. This is a 3 cylinder model. The displacement for the pistons is 49.7. The bore for this outboard is 3.0 inches and the stroke is 2.34 inches.
This engine has power steering and a electric-type starter. RPM Information: 4500-5500 Your engine's RPM range is important in choosing the right propeller for a given application. For example, if you look at your tachometer at top speed and it is not within the engine's RPM range then that is generally not good.
1979 Evinrude 4 Hp Outboard
You want your RPM's to be within the proper range while at wide open throttle (WOT). Be sure to do your testing under your normal boating conditions and with a good propeller (not bent, cracked, or excessively chipped). Information on this page is provided to you as a free service of iboats.com. Because this information has come from many sources we can not guarantee its accuracy. Even if this information is the same as the original factory specs, boats are sometimes modified. Thus, for safety and other reasons, it is a good idea to verify information here to make sure it matches up with your boat. The iboats are another excellent source of information.
Evinrude 70 Hp Service Manual
The iboats can likely help you find a lot of outboard information as it is arranged by subject. Engine Manual: Information on this page has come from multiple third parties and can not be guaranteed to be accurate.