Hi all,
I have spent hours and days trawling this forum to figure a lot out about my outboard but I am finally posting to contribute.
I have a Mercury 75HP 2 Stroke (I believe to be 2006) and I have had a low buzzing sound coming from my control - not a beeping just a crackling buzzing sound. Usually this occurs at high RPM - 4000 or at high speed on the plane. But occasionally very briefly at lower RPM but not often. I don't believe the motor is overheating as doesn't seem too hot and water stream great etc etc...
I have tried to go through all the solutions and finally today replaced the thermostat which was gummed up, corroded and had salt and sand on it. I cleaned the housing, replaced the gasket and cleaned the poppet valve. However, I realised that there was a big crack/piece missing in the housing for the Poppet valve - see picture.
Is this an issue?
When I bought the boat/motor it had just had some work done to it including pistons etc, don't have a list of things they did but it has been in really good condition except for this buzzing which is sending me mad.
I have done the spark plugs too.
Side note, took me 20 minutes to get the engine to turn over when I put it all back together and then eventually idled fine.. however when I put it into gear it was crackling a bit from the motor... will need to get on the water to be sure
Any help very very welcomed - happy to elaborate where I can.
Thank you
I have spent hours and days trawling this forum to figure a lot out about my outboard but I am finally posting to contribute.
I have a Mercury 75HP 2 Stroke (I believe to be 2006) and I have had a low buzzing sound coming from my control - not a beeping just a crackling buzzing sound. Usually this occurs at high RPM - 4000 or at high speed on the plane. But occasionally very briefly at lower RPM but not often. I don't believe the motor is overheating as doesn't seem too hot and water stream great etc etc...
I have tried to go through all the solutions and finally today replaced the thermostat which was gummed up, corroded and had salt and sand on it. I cleaned the housing, replaced the gasket and cleaned the poppet valve. However, I realised that there was a big crack/piece missing in the housing for the Poppet valve - see picture.
Is this an issue?
When I bought the boat/motor it had just had some work done to it including pistons etc, don't have a list of things they did but it has been in really good condition except for this buzzing which is sending me mad.
I have done the spark plugs too.
Side note, took me 20 minutes to get the engine to turn over when I put it all back together and then eventually idled fine.. however when I put it into gear it was crackling a bit from the motor... will need to get on the water to be sure
Any help very very welcomed - happy to elaborate where I can.
Thank you
