v150 idle issues

[thomasp]

hello everyone, im new to iboats and i need some help so i can get my boat running(my kids are wanting to go fishing) i have an 89 mariner magII 150. it does not start good and idles very rough when i put it in gear it wants to die. half to WOT runs very good. i removed the carbs and cleaned. i bought a spark gap tester and set it at about 1/2". i have good spark on every cylinder except #2. the coil is good because i switched 4 wire with 2 and i had spark so coil is good. i have service manual and an ohm meter but i do not have a DVA meter(wish i did). the ohm specs on the stator and trigger show to be good. i unhooked the spark advance module and still no spark. one other thing, sometimes when i first crank motor #2 might spark one or two times then thats it. also when i try to run motor for awhile then pull plugs, all the plugs look the same and are saturated with fuel. any help would be greatly appreciated and if i need to purchase a vda to troubleshoot the stator, trigger, and switch boxes i geuss i will.
thanks

 

[Don S]

Re: v150 idle issues

You might try switching the switch boxes and see if the one with faulty spark changes sides.
Might also pull the flywheel and check the magnets. Loose ones can cause problems like that.

 

[thomasp]

Re: v150 idle issues

i switched the switch boxes and now i have spark on #2 but i lost it on 1 & 3. the spark on most cylinders seems to be intermitent. i cant seem to get a good conclusion with my spark gap tester on all cylinders. a mechanic told me if it was the stator i would have spark on just three cylinders, he said it sounds like it might be a switch box or two. does anyone have any opinions.

 

[Don S]

Re: v150 idle issues

Put it back and see if it goes back to #2 not firing.
Sounds like a bad switch box to me.

 

[bhive]

Re: v150 idle issues

If it is the switch boxes you must replace both of them. The reason is the one that is working may have caused the failure in the other one.

 

[thomasp]

Re: v150 idle issues

thanks for the replies. i ordered 2 new sierra switch boxes today and i will let you know if they fix my problem

 

[hkeiner]

Re: v150 idle issues

Based on my past experience, IMHO it is a better finanical bet to first spend money on a DVA meter (to test and confirm that an expensive ignition component is defective) before spending money on replacing such components.

 

[studlymandingo]

Re: v150 idle issues

I have had some spark issues in the past; once it was my stator. Subsequently, I have had issues with the wires going from the switchbox to the coils. I have been replacing them one by one as they went out. I am going to go ahead and replace the last three this afternoon as I am thinking it will be easier on dry land than trying to do it from the swim-step like I have done for the first three.

 

[castaway68]

Re: v150 idle issues

by switch boxes,,i assume that is what i would call a power pack?

 

[thomasp]

Re: v150 idle issues

there is a very good mechanic near my house and i would have taken it to him, but he is booked for one year. i told him what it was doing and he said it sounds like a switch box. he also told me to do 3 other very important things to my motor. 1: disconnect the advance module and toss in trash. 2: replace oil pump bushing with new style bushing. 3: replace old style check vavle on bottom right side of motor with new style which is smaller.

 

[ronnieboy]

Re: v150 idle issues

i gotta 88, 150 mag II, lost a pack and replaced it below kentucky lake dam, been runnin ever since, please explain last message, # 2 and 3, why change? ron

 

[thomasp]

Re: v150 idle issues

installed my 2 new sierra switch boxes and she runs like new again. thanks for the advice.