throttle control adjusting

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pyro225

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hi guys, i had a merc stack 6 on one of my boats and the throttle setup was spot on but the ob died so i replaced with a similar aged merc 50 4cyl. i put the throttle cable in as they were and the went in fine. unfortunately a few bolts sheared when doing so so they are almost permanent/long job to adjust ob side now.

So the problem is my acceleration jumps so there no power until 45degrees on the throttle and i have to go past 90 degrees for wot, and the power jumps in stages not smooth like it was. can i adjust cables at control end? and which way would i adjust? also when backing off wot it jumps massively down... cheers
 
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Chris1956

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The operation of your control sounds about right. I would guess you have some kind of engine issue. Maybe the spark is not advancing smoothly or the synch is off?
 
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pyro225

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hi chris - when i hadn't got controls connected i could smoothly rev up and down the engine by using the throttle arm under the cowling so engine is fine i think its just the adjustment needs tuning but need to know if i can do throttle end as above
 
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Chris1956

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As far as I know the control end of the throttle cables are not adjustable. Also revving the motor in neutral is not a real world test.
 
Texasmark

Texasmark

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Chris1956 said:
As far as I know the control end of the throttle cables are not adjustable.
Click to expand...

Agree. Adjustment barrel is on the engine end. If things were working fine before and not now, possibly you are binding in an area where you weren't binding before. Cables don't like sharp bends and if you accidentally kinked an inner cable when doing the installation, the cable will never respond as it did.
 
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pyro225

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ok worst case i have to adjust ob end whats the best way to get correct adjustment?
 
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Chris1956

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Put motor into neutral. Put throttle handle into neutral, cold start lever down. Open control cable clamp at motor and remove throttle cable. Now adjust shift cable until cable barrel nut is centered in holder and shift lever centered in neutral. Push throttle closed, against stop. Adjust throttle cable barrel nut to add some preload, and push it into clamp and close clamp.
 
Texasmark

Texasmark

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Chris1956 said:
Put motor into neutral. Put throttle handle into neutral, cold start lever down. Open control cable clamp at motor and remove throttle cable. Now adjust shift cable until cable barrel nut is centered in holder and shift lever centered in neutral. Push throttle closed, against stop. Adjust throttle cable barrel nut to add some preload, and push it into clamp and close clamp.
Click to expand...

I add pre load on the WOT end of the spectrum, not the idle end. I can make up for any slop there by the engine's idle rpm set screw. At WOT you have what you have.
 
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pyro225

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Hi Guys, I'm really struggling - i had 3 jobs to do on my outboard, install the choke lever as it had a bit of wire before - DONE, was stalling when in idle, that was most probably because the idle screws were all the way in so was told on here to unscrew both 1.5 turns - DONE, try to adjust these throttle cables - DONE but not improved... when i push throttle forward it still goes forward about 2/5 of the way before the throttle cable starts pulling, it takes this 2/5 to go into gear. i set the cable to as close as it could in neutral to going into forward gear while still being in neutral.

These cables were on my 90 tower of power on the same boat and worked fine so no they are good, but still feels wrong.

Now the big problem - i pulled it about 100 times and it won't start? any ideas based on the above? i revved it out in neutral as well.

Any ideas? if i have the gear selected right on the edge of neutral near forward would that effect it? would it even start in gear?

Need advise guys thanks
 
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Chris1956

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Pyro, Take it easy or you will break something. Normal control box operation is as such: The throttle arm is in neutral at 12:00. At about 2:00 it is in forward. At 4:30 the throttle is at max speed. Center the shift cable in neutral when the throttle arm is in neutral, as I had posted.

BTW - wire was used by Merc on all the manual choke knobs, for years.

So you have the carbs set to initial opening of 1.5 turns out from light seating, that good.

Do you have spark? Is the compression good? Spray some 50::1 fuel into the carbs and see if she will fire. If so, it is likely the carbs are a problem.
 
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pyro225

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Hi Chris - so my lever positioning is correct? i was worried i had misaligned the lower unit when i last did the pump a while back - but it did seem to go ok. so you are saying the throttle cable shouldn't move until the lever is at 2oclock?
Would it start in gear out of curiosity?
The big brass screw on the top of each carb out yes 1.5 turns.

Tried the bad way to start already a bit of easy start in the carb and that wouldn't fire either... you can hear excellent compression when you are pulling as well i had a look or loose wires inside wondering if theres a loose kill wire but couldn't see anything?
 
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Chris1956

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The video looks like proper operation of the throttle lever to me.

clearly loose wires on the motor is not good. Could they kill spark- definitely. You have the 4 coil ignition or the distributor ignition?
 
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pyro225

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Hi Chris, I do indeed - I believe its the last of the bluebands so the half decent tech :)
 
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pyro225

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Chris/Guys

Took a look at the plugs today they were a little fouled so replaced them and one had a crack in the ceramic so changed that also... only thing is I looked in my box and I had 2 buhw-2's and 2 buzhw-2's I put two on one carb and two on the other... firstly is the z plug any different to the non z and is what I've done a problem...

Not sure if I have fixed the starting issue as its warm now but it starts ok need to keep you posted...

Ok next up the bad idle... still bad... just a recap there are two brass screws with two small holes at the top and a long tube with a hole in it, all are nice and clean.

When I have them wound right in, it runs ok if you leave the throttle in idle at about 11'oclock. However when I bring back to 12oclock it stalls. If I wind out both carbs 1 - 1 1/2 turns it makes it worse it bring the idle right down and stalls even easier - I need to keep it at maybe 10 o'clock to keep it running? What's my next move? as mentioned before I recently did a carb / plug clean?

Below are a few videos showing my issues...
https://www.youtube.com/watch?v=-Mfmqn4ysVI
https://www.youtube.com/watch?v=AQfUgXLqYAo
https://www.youtube.com/watch?v=CMR8RL5stSU

Advise very muchly appreciated :)
 
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