87 150 prov won't rev

[imported_bronzeback]

I am fairly new to boating so forgive my ignorance,but here goes.I have a 18' ranger with the 150 yamaha that
has ran resonably well since I bought it,but friday night
it stated slowing down it droped from 5000 rpm to 4000rpm then surged back and forth between 4000-4600 never getting above that. I had to drop off of plane
to go through a idle zone and it wouldn't get the boat back on plane after that.It will get up to about 2000rpm
and run for a while then start bogging down if you flip the choke on for a few seconds and let off it will run back
up to 2000 again.It also has developed a hard miss that will almost kill the motor at idle.I changed the plugs and checked the compression (all 6 were 100psi) i haven't gotten back to the lake but the miss is still there when running on the waterhose.I checked the new plugs and all were slightly wet.i also checked each coil with a dry plug and they all were firing but didn't seem like a very intense spark.Any help would be greatly appreciated and sorry if i have rambled just wanted to be thorough.

 

[Ray Neudecker]

Re: 87 150 prov won't rev

Sonds very much like fuel starvation. You need to go through the system from tank to carbs.