1991 pro v 150 help

I have been having trouble with the holeshot. I have replaced the spark plugs. they were fouled? I checked the link and sync and cleaned the carbs. I also checked the compression I had 110psi on all of them with only a few psi differance between them. I checked the coils and they seem to be sparking. I replace the fuel pumps and checked fuel pressure all was ok. but It seems to only be running on 4 cyl, the middles ones are dead. When I put my hand over the center carbs I have barely any air flow sucking into them, the bottom carb has a lot of air the top carb has some air but not a lot. Could this be the reeds? at this point I have no clue what else to check.

[jb123]

hows it run up hi?

run motor on hose at about 1200 rpms, pull each plug wire at a time ensuring a power loss sound. youre lookin for a non firing cyl so if one desnt make a change , try 2 and alternate.

then you can pull airbox and choke each throat with your finger, listenin for an increase in sound/rpms.

the usual suspect is dirty carbs.

reeds would spit back from crankcase pressure.

I did that and no change on the middle 2 cyl. when I have the airbox off and I choke the carb with my hand nothing happens. there is really no air trying to enter the carb. Its like the reeds are stuck closed. we cleaned the carbs and the looked clean. If the carb was dirty would it still try to draw air into it? I would think that it would it just wont get any fuel.

If the reeds were stuck closed how could it spit back at the front of the carbs. I guess its the airflow or lack of into the carbs I don't understand.

Its seems to run better at higher rpms. but its hard to tell when running off the garden hose.

[jb123]

you could swap reeds but if it runs better up hi then they are working.

im not positive in `91 if those 2 cyls shut down at low rpms or not, thats why you need to test up higher a bit.

can I still test it up high in rpm with the water haose.

Is there a way I can find out if those cyls are suppose to cut out at low rpms
thank you!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[Hamfisted]

Rebuild the carbs....

Have you actually taken the carbs off and torn them down and cleaned them out? I mean pulled the bowls off and each jet and orifice cleaned out? Did the boat sit up for a while without being run? Those old carbs were very prone to clogging if they sat for any length of time without being run. There's also some orange O-ring seals on the inner ends of the main jets that may crack over time and allow unmetered fuel to pass around the main jets and flood the motor out and mid to high rpm throttle settings. If they have never been replaced before I would take a close look at them. Do you have a factory service manual for the motor? If not, get one. Your problem is not your reeds. And those motors do not shut down any cylinders intentionally under normal operations.




- Mike