Carburator Adjustment 150 HP Force

[eavdic10]

Hi Guys,
Got a 1989 150 HP Force with 3 carbs and last weekend took it out and at full thorttle it lowers and increases RPMs by itself. NOT too much but noticable if you pay attention. I am thinking carbs clean first, do you think could be something else? Also on the carbs there is one screw for the idle with the spring and there is another white one I think that one is for air. Can see pictures below. What is the standard how much should those be turned out?

 

[jerryjerry05]

Re: Carburator Adjustment 150 HP Force

The white(dirty)thing is a plug.Don't touch.It covers a jet.
Remove the cover only if your cleaning the carb.
The screw with a spring(air screw) turn it in to the bottom(gently).
Then out 1 and 1/16 turn out and leave them.
The idle is adjusted from the towershaft on the side of the motor.
They look pretty dirty on the outside.
Makes me wonder what they look like on the inside????
The flucuation??? It could be the choke/enricher feeding fuel to the system.
It can be isolated by pinching off the feed tube.
If it's the enricher.It's a replace no repair.
Do a compression/spark test.

 

[eavdic10]

Re: Carburator Adjustment 150 HP Force

Thanks for the reply, what is a chocke enricher? is it the little tube with button in the middle do you mean to pinch that tube? I just feel like the boat does not get the full rpms it needs... Compression is 130 across all 5 cylinders. I will install a tach tomorrow and see where she runns wot but what is it supposed to be at WOT is it 5500 RPMS not sure what prop I should have so might be it as well. IF I am overproped.
Thanks for input