40hp Merc Issue

Cox

Seaman
Joined
Sep 19, 2008
Messages
65
Posting for a friend and waiting on plenty of additional information including Serial Number. 40hp Tiller approx 2000 Model Year. Basically says that motor does not respond until throttle handle is turned 50% of the way. I know there are a lot of moving parts between throttle arm, through linkage, etc. Just looking for some logical starting points in terms of the most likely root of the problem. Any help appreciated. Will post additional information when I have it. Thanks!
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
I would eliminate a dirty/partially plugged fuel system first.
If carb(s) remove it remove everything clean well, remove a welch plug if you have it.
If you have fuel injectors, clean them install new fuel filter on the fuel injector. It's on youtube.
Install a fuel water separator, and new on motor fuel filter.
If the fuel lines are over eight years old replace with USCG A1 fuel line, new primer bulb.Take a fuel line off and see if its soft/gooey inside, If the fuel line has a lining on the inside replace immediately.
Odds say she's starved for fuel.
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
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49,038
I would eliminate a dirty/partially plugged fuel system first.
If carb(s) remove it remove everything clean well, remove a welch plug if you have it.
If you have fuel injectors, clean them install new fuel filter on the fuel injector. It's on youtube.
Install a fuel water separator, and new on motor fuel filter.
If the fuel lines are over eight years old replace with USCG A1 fuel line, new primer bulb.Take a fuel line off and see if its soft/gooey inside, If the fuel line has a lining on the inside replace immediately.
Odds say she's starved for fuel.

This sounds more like a throttle linkage problem, nothing warrants doing the things in this post. ^^^^.

Once we have the serial number, then we can give worthwhile advice. Some tillers use a short cable and others use linkage rods.

One thing you can check to look at the throttle plate and see if it opens as the throttle is twisted or if it starts opening about the 50% twist you mentioned.
 

Cox

Seaman
Joined
Sep 19, 2008
Messages
65
Serial Number is 0T680891. It has Cable linkage from what I see in the pictures. I?ve got a video and a pic but I can?t seem to get them posted. Been awhile since I?ve posted Pictures on here.
 

GA_Boater

Honorary Moderator Emeritus
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Look at the Forum Help link in my sig, Cox. Usually something simple or a missed step when adding pics and vids. Hope so.
 
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Cox

Seaman
Joined
Sep 19, 2008
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65
Hoping this link worked. This is a video of the Linkage cable (I think) with some extra play in it as the throttle is moved about 50% before the motor engages.
 

GA_Boater

Honorary Moderator Emeritus
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That uses a pair of push-pull type throttle cables. It looks like there is too much slack in the cables by the way the cable loops on the opposite side as you open and close. One side isn't pulling as the other side pushes.

Are the cable ends threaded? It looks like a pair of adjustment nuts on either side of the cable retainer that can be used to take up the slack.

cableadj.PNG

I don't have access to a manual for your motor. Maybe one of the other guys has a way. I'll keep looking for a manual.
 

Cox

Seaman
Joined
Sep 19, 2008
Messages
65
He tried that nut, but said it didn?t adjust the slack at all. Not sure if he has ordered the Seloc manual yet but I did advise that and I believe he plans to. Let me know if you have any other thoughts in the meantime, thanks!!
 

Chigwalla

Petty Officer 2nd Class
Joined
Jul 11, 2017
Messages
109
FWIW, I added a tiller handle kit to a 20hp a while ago. It did take some fiddling to get the cable adjusted just right, and that was on a brand new motor.
The nuts that GA_Boater pointed out are indeed the adjustment nuts for the cables.
If you've run out of adjustment range, the cables have stretched over time and need to be replaced (not an overly common problem, but not rare either).
 
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