Fuel problem Mariner 3.5hp

[philpollard]

I've had the same problems with my Mariner (Mercury) 3.5hp as others in that it'll start and tick over but dies on throttle.
Flitted a new fuel valve and discovered the old filter had come adrift and was half way along the fuel pipe between the fuel tank and the valve. Going to fit a 5hp carb as an upgrade and hopefully back in business.
Thought I'd share this experience. Basic but could be of use to someone else!

 

[steveallan]

I've had the same problems with my Mariner (Mercury) 3.5hp as others in that it'll start and tick over but dies on throttle.
Flitted a new fuel valve and discovered the old filter had come adrift and was half way along the fuel pipe between the fuel tank and the valve. Going to fit a 5hp carb as an upgrade and hopefully back in business.
Thought I'd share this experience. Basic but could be of use to someone else!

You may need to change the prop to get the full benefit of the 5HP carb.
Also expect fuel consumption to increase.

 

[philpollard]

You may need to change the prop to get the full benefit of the 5HP carb.
Also expect fuel consumption to increase.

Thank you Steveallan

 

[Steve65]

I've had the same problems with my Mariner (Mercury) 3.5hp as others in that it'll start and tick over but dies on throttle.
Flitted a new fuel valve and discovered the old filter had come adrift and was half way along the fuel pipe between the fuel tank and the valve. Going to fit a 5hp carb as an upgrade and hopefully back in business.
Thought I'd share this experience. Basic but could be of use to someone else!

You need to increase your main jet size

 

[Steve65]

Or check you haven't got a vacuum leak on your intake manifold where it bolts to head and also carb gasket

 

[philpollard]

Or check you haven't got a vacuum leak on your intake manifold where it bolts to head and also carb gasket

Or check you haven't got a vacuum leak on your intake manifold where it bolts to head and also carb gasket

Hi steve65, that's all fine. New carb on and started . Okay on throttle now. Idling needs adjustment but I think we're nearly there. Thank you anyway.

 

[nevis768]

I've had the same problems with my Mariner (Mercury) 3.5hp as others in that it'll start and tick over but dies on throttle.
Flitted a new fuel valve and discovered the old filter had come adrift and was half way along the fuel pipe between the fuel tank and the valve. Going to fit a 5hp carb as an upgrade and hopefully back in business.
Thought I'd share this experience. Basic but could be of use to someone else!

I've got a 4hp, and find these problems if I use petrol more than a couple months old. Which are then cured by cleaning the carb and jet. If I keep the petrol fresh, there are no issues.