Expert: Everett Peacock - 5/19/2010

Question
Hi I have a power problem with my outboard, this is the second time this has happened.
In normal operation the motor will rev out to 5500rpm but at the moment it will only go to 4500rpm. The first time this happened we were travelling very slow for an extended period of time and I assumed the plugs had oiled up so I ran it at 4000rpm for 2 hours and there was no difference. Removed the plugs and cleaned/checked them and that made no difference. Changed the oil to yamalube and took the boat out and it coughed and spluttered for a while then the extra power and revs came back.
The 4 months later everything was ok didn't use the boat for 1 month and the same problem is back.
The boat looses power and revs.
The throttle works to a point then the last 1/4 has no response.
When the cowling is removed you can see the throttle lever move and then for the last 1/4 another lever is engaged on that is when there is no response.
Hope you can help

Answer
I think what you are seeing is is the timing base...it turns about 30 degrees and then the carb butterflys move...

does it run ok and then just boggs down ?  how long does that take for that to happen ?
check your compression and spark on all cylinders....
let me know what you find...
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