'96 225 Merc HELP!

Luis1127

Recruit
Joined
Mar 22, 2010
Messages
4
Hey all,

I have a '96 225 Mercury Carb and it surges at high RPM. I changed the fuel lines, filters and checked the tank for bad gas, still nothing. I was told by the previous owner he had changed the stator and he had redone the carbs not too long ago. I also noticed some spark plug wires seemed kind of cracked on the outside. I was hoping you guys can answer some questions for me:

1. Are cleaning the carbs on this outboard extremely dificult? I have the manual (I used to do it on my 200hp Suzuki with no manual) and is it necesary for my to buy the entire rebuild kit($98 x 3) or can I get away with just cleaning and new gaskets since they have been rebuilt not too long ago

2.Can the spark plug wires be changed or do I have to buy the entire switcbox? (I believe it goes directly from it to the plug)

I believed it to be a fuel problem, but don't know if it can be the plug wires. Any and all sugestions are welcome

Here is a video of another engine doing almost the same as mine, just mine does get up to 5300-5400 RPM at times

http://www.youtube.com/watch?v=xMfO8gfvNi0

Thanks
 

IGIFF

Cadet
Joined
Mar 22, 2010
Messages
26
Re: '96 225 Merc HELP!

Plug wires can be purchased seperately.Carbs easy to clean.You have not mentioned the fuel pump,these kits are very cheap and should be replaced every couple of years as a part of the service.When running the motor at WOT try squeezing the primer bulb to see if it rectifies the problem indicating a fuel supply problem.
 

Luis1127

Recruit
Joined
Mar 22, 2010
Messages
4
Re: '96 225 Merc HELP!

Thanks IGIFF,

Sorry I forgot to mention the fuel pump, I am planning on buying the kit for it, as far as squeezing the bulb while at WOT, I did try it and got no response which is why it leads me to believe it is either at the carbs or something electrical.

Any clue?
 

IGIFF

Cadet
Joined
Mar 22, 2010
Messages
26
Re: '96 225 Merc HELP!

If squeezing the primer bulb makes no difference then you need to try the following to work out what is going on.Firstly,take the air intake cover off .get a flash light and run the motor till it surges whilst watching the inside of the carbs,if it is a fuel problem you will clearly see irratic fuel flow from one of the venturies indicating a fault with that carb.DO NOT DO THIS FOR LONGER THAN is neccessary because the air ram effect will lean out the mixture although it will not hurt it doing this for 30 secs or so.If this is OK then I suspect an irratically firing coil or lead.This is more difficult to diagnose but you can use a timing light connected to each cyl one at a time and watch the strobe to see which on is irratic or mis firing.Once this is done you can let me know and I will tell you how to identify the faulty component.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,589
Re: '96 225 Merc HELP!

He changed the stator and he had redone the carbs not too long ago
Did he reset/adust the TPS sensor on the top carb? If out of adjustment will cause bogging and top end problems.

Are cleaning the carbs on this outboard extremely dificult?
No...
Can the spark plug wires be changed or do I have to buy the entire switcbox?
Yes as they plug in the CDM module but check your serial number first as there is one model that has a coil assy like the Yammy coil and they are NLA from Merc.
Sorry I forgot to mention the fuel pump, I am planning on buying the kit for it
Try this first.... and if it still does it unplug the temp sensor off the starboard head and retest.
 
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