1996 150hp yamy. helpin a friend

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Hello, I just purchased a 1996 150hp Saltwater series 2. When we went to look at the boat and motor, the motor seemed to idle fine on the hose. So the next day we brought it home and went to take it out on the lake. The motor was somewhat difficult to start. Once started, the motor wont idle and runs very rough when up to speed. When you drive it, you can feel 1 or more of the cylinders cutting in and out. So I rebuilt all 3 carburators to no avail. Next we confirmed spark on all 6 cylinders. After fiddling around with it all day, we came to the conclusion that it doesn't run any different without the bottom two sparkplug leads on. We confirmed again that they both have spark. Both cylinders are fed fuel by the same double barrel carburator. I took it apart and went through it again making sure this time to check every little thing. Cleaned it again, put it back on, No results. At this point I am stumped.... The fuel pumps seem to be fine and all the carbs seem to be getting proper fuel supply. The compression is all good. No idea. Was looking for a "Had the same problem, try this" sorta thing. Any help would be greatly appreciated!!!


ummm soo id thought id give a friend some help sooo here's his post from another website.

he tested the motor on the muffs which is a big no no. sooo he saids all 6 have good spark. good compression but idk. bottom 2 cylinders seems to have no effect on the engine. it kicks in at high speeds then comes off. im thinking fuel problem.
 

erniefish

Petty Officer 2nd Class
Joined
Dec 11, 2007
Messages
153
Re: 1996 150hp yamy. helpin a friend

i just had very similiar issue, check to see if re-circ valves are working( i had 4 bad ones) i hope this helps good luck
 

coolguy147

Commander
Joined
Jul 14, 2008
Messages
2,817
Re: 1996 150hp yamy. helpin a friend

recirl vales for what? oil lines? i havent seen the motor yet. umm? check valves? check by blowing and sucking on lines?
 
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