70 hp wont open up

[fleetwin10]

70 hp yamaha model 70tlrc wont open up, when you push throttle all the way open it will only run about half throttle or maybe less

 

[guyjg]

Check the condition of the spark plugs...should be medium brown in color. You can remove one plug wire at a time w/insulated channel locks while idling to see if the motor runs rougher to verify all plugs are firing. Or verify each spark plug wire end is getting spark to the plug...use a plug wire gap tester set at 7/16" gap. You gan make one very easily or get one at a parts store. You want to see a blue snapping spark.