Hi to all boat folks, greetings from Sweden!
My 1975 Evinrude 70 hp (model 70573B) has recently developed this issue where it stalls while putting into gear and revving the engine. You can see it happening in this video recorded earlier today: https://youtu.be/3IfztThmwsg.
I've had this boat during 4 years and it has been running really good all the way, except for the last couple of weeks. It seems like an intermittent issue. A couple of minutes before this video was recorded I had it running normally, see this video https://youtu.be/7Jzbl2AJUk8. Then suddenly it starts hesitating under load, surges, and then I can only start in idle.
The problem first arose after a 2-3 hour trip two weeks ago, quite heavily loaded 6 people onboard and packing for weekend on a remote island here in the outer Stockholm archipelago. Engine worked pretty good, no problems on the way out. The day after, I added fuel from my 2 times 25 litres extra cans I brought, to get us home. During this trip home the first signs developed, slightly hesitating but nothing serious at first. Since then the problem has worsened.
Just before this summer season, I put in 3 new ignition coils (3 cylinder engine) because the old ones had cracks in them, changed as preventive measure. New spark plugs Champion J4C like the manual calls for. Engine running great after new coils installed.
Now when this issue developed I first suspected carburetor issue or compression loss. Tested compression all three cylinders are at approx 130 PSI (132, 132, 130), nothing suspicious here. Then I turned my attention towards carburetors. I got the carb kits from Sierra and refurbished all three carburetors. No noticable dirt in any of them but cleaned them out good anyway and put new gaskets in, fine tuned float settings etc. Also put in new fuel line from the bulb on, to the engine. Inside engine housing I renewed all fuel lines from the incoming fuel connection to fuel pump, and from pump to main carb.
At home with water hose it started right away, kind of did a high five and took it back to the water for a real spin. It ran pretty well after the carb service, about 10 minutes without problems then again it started stalling.
As next step I have emptied the whole fuel tank, took out 50 litres, took the aluminium tank out of the boat, had it upside down, rinsed with fuel and shaking everything out to make sure nothing strange is inside the tank. Got everything back in place and now I'm holding my thumbs it will be running better than this...
Does anyone have any previous experience or knowledge on this type of behaviour in Evinrude 3 cylinder two stroke from the seventies?
My 1975 Evinrude 70 hp (model 70573B) has recently developed this issue where it stalls while putting into gear and revving the engine. You can see it happening in this video recorded earlier today: https://youtu.be/3IfztThmwsg.
I've had this boat during 4 years and it has been running really good all the way, except for the last couple of weeks. It seems like an intermittent issue. A couple of minutes before this video was recorded I had it running normally, see this video https://youtu.be/7Jzbl2AJUk8. Then suddenly it starts hesitating under load, surges, and then I can only start in idle.
The problem first arose after a 2-3 hour trip two weeks ago, quite heavily loaded 6 people onboard and packing for weekend on a remote island here in the outer Stockholm archipelago. Engine worked pretty good, no problems on the way out. The day after, I added fuel from my 2 times 25 litres extra cans I brought, to get us home. During this trip home the first signs developed, slightly hesitating but nothing serious at first. Since then the problem has worsened.
Just before this summer season, I put in 3 new ignition coils (3 cylinder engine) because the old ones had cracks in them, changed as preventive measure. New spark plugs Champion J4C like the manual calls for. Engine running great after new coils installed.
Now when this issue developed I first suspected carburetor issue or compression loss. Tested compression all three cylinders are at approx 130 PSI (132, 132, 130), nothing suspicious here. Then I turned my attention towards carburetors. I got the carb kits from Sierra and refurbished all three carburetors. No noticable dirt in any of them but cleaned them out good anyway and put new gaskets in, fine tuned float settings etc. Also put in new fuel line from the bulb on, to the engine. Inside engine housing I renewed all fuel lines from the incoming fuel connection to fuel pump, and from pump to main carb.
At home with water hose it started right away, kind of did a high five and took it back to the water for a real spin. It ran pretty well after the carb service, about 10 minutes without problems then again it started stalling.
As next step I have emptied the whole fuel tank, took out 50 litres, took the aluminium tank out of the boat, had it upside down, rinsed with fuel and shaking everything out to make sure nothing strange is inside the tank. Got everything back in place and now I'm holding my thumbs it will be running better than this...
Does anyone have any previous experience or knowledge on this type of behaviour in Evinrude 3 cylinder two stroke from the seventies?