classicevinrude
Cadet
- Joined
- Jul 29, 2008
- Messages
- 25
Hello all,
I have a 1999 Yamaha 9.9 Four Stroke (F9.9MSHX). The motor has been running progressively worse since last fall. This spring I performed a full maintenance program. I changed the oil (lower unit and engine with YamaLube), replaced the external Yamaha Fuel/Water separator, rebuilt the carb with the Yamaha kit and replaced the internal inline fuel filter. Last summer we replaced the tank and fuel line as well as installed the water separator.
However, it still runs very poorly. It will not idle and appears to have a massive air leak. If I spray carb cleaner at the area between the intake manifold and carb, the idle will even out and the motor will run ok. When I rebuilt the carb I observed that there was a gasket sealer on the intake manifold and the carb mounting flange. It looks like 3M 847 that melted and was drawn up the intake. So, I cleaned up the mess, replaced the gaskets and put it all back together to no avail.
What should be my next step? There is a plastic spacer block between the manifold and carb (manifold-gasket-spacer-gasket-carb). Should I remove the carb and sand the mounting flange as if I was flattening a cylinder head? Should I replace the spacer block? I really think gasket sealer was some other mechanics quick fix, it failed and the problem returned. Me fixing this outboard was supposed to be my dads father's day present, but it did not work out. He was happy just at my efforts but I want to get to the bottom of this.
Thank you for any and all suggestions that you can offer.
Forrest
I have a 1999 Yamaha 9.9 Four Stroke (F9.9MSHX). The motor has been running progressively worse since last fall. This spring I performed a full maintenance program. I changed the oil (lower unit and engine with YamaLube), replaced the external Yamaha Fuel/Water separator, rebuilt the carb with the Yamaha kit and replaced the internal inline fuel filter. Last summer we replaced the tank and fuel line as well as installed the water separator.
However, it still runs very poorly. It will not idle and appears to have a massive air leak. If I spray carb cleaner at the area between the intake manifold and carb, the idle will even out and the motor will run ok. When I rebuilt the carb I observed that there was a gasket sealer on the intake manifold and the carb mounting flange. It looks like 3M 847 that melted and was drawn up the intake. So, I cleaned up the mess, replaced the gaskets and put it all back together to no avail.
What should be my next step? There is a plastic spacer block between the manifold and carb (manifold-gasket-spacer-gasket-carb). Should I remove the carb and sand the mounting flange as if I was flattening a cylinder head? Should I replace the spacer block? I really think gasket sealer was some other mechanics quick fix, it failed and the problem returned. Me fixing this outboard was supposed to be my dads father's day present, but it did not work out. He was happy just at my efforts but I want to get to the bottom of this.
Thank you for any and all suggestions that you can offer.
Forrest