1991 Force 70 HP midrange miss

Buckrub Doug

Recruit
Joined
Jun 26, 2017
Messages
4
Good afternoon all! I have gotten alot of help of the last couple weeks just reading posts and decided to join up as I do have an issue.

I have a 91 Force Model 706F91B. It is on my 20ft Pontoon boat
I seem to have what I call a midrange miss. Runs fine on idle, but when I start to climb off of idle it seems to be a popping or miss.
Here is what I have done/checked:

Carb was cleaned 2 times
Checked WOT timing (while cranking) its at 32 degrees
All plugs are clean. New NGK BUZHW

Here's what I dont understand..My timing rod is all the way into my block and the locknut is on the inside of the block. All my pictures in the Force service manual show the nut on the outside of the block and the rod about a 1/4 inch out. I have also seen peoples videos and pictures online and theirs are all about the same. (I will post a picture when I am allowed)
Now when I was trying to check my timing while running, my light kept shutting off as I was throttling up to WOT (prop off) Am I not supposed to do that? Does it sound like a possible coil going bad or a Switchbox? I am so lost right now..
I have not checked the coils or switchbox yet, its kinds hard to do on the back of a pontoon boat..lol
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
This motor has the Mercury ignition.
The position of the rod doesn't necessarily have to be 1/4" out.
That depends on who set it up?

​Some outboards have a high and low speed stator which could cause a miss.
​I don't think yours has it.
So if you have fire at low speed you should have it at high.

The mid range miss: could be the reeds behind the carb.
​These 70hp frequently had reed problems???
 

Buckrub Doug

Recruit
Joined
Jun 26, 2017
Messages
4
I was going to buy some reeds just to replace them since I will be taking it apart. Does anyone sell the reeds separate? It a good chuck of change to replace them all if all I can buy are housings! WOW!
 

Buckrub Doug

Recruit
Joined
Jun 26, 2017
Messages
4
Reeds look fine, still dont like how the timing rod is so far into the block. i rechecked timing and reset now it doesnt start. maybe i am using my advance timing light wrong?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
You don't need an advance timing light.

Do the static timing described in the top post.
 
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