This is NOT my boat. The boat is a 21' Pontoon with a 40 HP Yamaha. The engine had been on a steady diet of the cheapest 2-cycle oil available and had infrequent use. The boat finally sat over a year with no storage provisions on the engine ever. This engine would barely run and smoked real bad.
Replaced all fuel hoses and changed plugs. Fresh fuel with Amsoil AIO Injector oil even though this engine is a pre-mix at 100:1. Mixed Amsoil at the correct ratio and the engine started to run more normal.
I gave them some Amsoil Saber Outboard Synthetic (ATO) 100:1 pre-mix. It was in 8 ounce bottles. A full bottle with 5 gallons of fuel gives a 80:1 ratio. Now running it at that ratio. I like a heavier ratio in boat engines in the summer when water temps are over 80 degrees and can run to 94 at times. Smoke is reduced to almost nothing at idle, and running it is not visible.
The Amsoil seems to have cured the problems and is still cleaning the engine. Next project is to remove the built-in fuel tank and clean and install an in-line water/fuel separator.
Replaced all fuel hoses and changed plugs. Fresh fuel with Amsoil AIO Injector oil even though this engine is a pre-mix at 100:1. Mixed Amsoil at the correct ratio and the engine started to run more normal.
I gave them some Amsoil Saber Outboard Synthetic (ATO) 100:1 pre-mix. It was in 8 ounce bottles. A full bottle with 5 gallons of fuel gives a 80:1 ratio. Now running it at that ratio. I like a heavier ratio in boat engines in the summer when water temps are over 80 degrees and can run to 94 at times. Smoke is reduced to almost nothing at idle, and running it is not visible.
The Amsoil seems to have cured the problems and is still cleaning the engine. Next project is to remove the built-in fuel tank and clean and install an in-line water/fuel separator.