Idle adjustment or throttle adjustment?? 1974 1150 TOP

[DylRod94]

Boat runs great out of water (besides getting it to start ) so I took it to the lake this morning for the maiden voyage and started it up let it warm up for a bit. (Had to manually prime the engine (pull plugs and pour gas in) ran great after) pushed it off the trailer and went to put it in gear and it dies every time I put it in gear. The motor hardly idles whenever the cold star idle levee is halfway. When pushed all the way forward it idled around 1100 rpm. So if this a throttle cable adjustment or idle screw adjustment??

 

[jimmbo]

Both. With the throttle cable unanchored, you set the idle speed with the idle stop screw, then adjust the cable length so there is just a slight preload holding the linkage against the idle stop

 

[DylRod94]

With the gear in netrual and the idle lever all the way forward what should the Rpms be? Also when I put it in forward gear out of water the idle lever comes to the middle (sticking straight up) and when I push the idle lever back forward there is no change in RPM. Is that normal ?

 

[Chris1956]

The cold start lever is not adjustable. Follow Jimmbo's procedure to set the idle speed, and the cold start lever will be what it is. In addition, the carbs need to be slightly richer than expected to allow the motor to run in gear at idle.

On a flusher, I would recommend the idle (cold start down, engine warm) to be 1000 RPM. If she still dies when put in gear or if the boat will not accelerate, the carbs need attention.

 

[DylRod94]

What gives the boat throttle then? The left lever moves in into forward that's it. Once that happens it raises the idle lever to sticking straight up. I assumed you press it back down to give it gas

 

[DylRod94]

When I pressure forward on the left lever to put into forward it doesn't kick into gear till pretty much the main bottom and the rpms do not change at all

 

[jimmbo]

Does your control box look like this?

 

[DylRod94]

Yes

 

[merc850]

Here's the cable setup procedure; the shift cable moves first then the throttle with the cold start lever down

 

[jimmbo]

Ok, the tall lever is gearshift/throttle lever. Push it forward to shift in forward, push it further for throttle. WOT is at about the 8 oclock position, with most of the gogo happening in the last bit of movement. Pulling it back past Neutral will do the same for reverse. The shorter lever on the other side is the start/warmup lever. It only controls the throttle for a limited range. Push it back down before shifting.
Also, this is IMPORTANT! Do not ease it into gear, that just wears the expensive parts out. These motors are either in or out of gear, so smartly and decisively shift into forward or reverse at low idle speeds. If engine dies going into gear, either the speed is set too low, the idle mixture is too lean, or it is not running on all cylinders

 

[DylRod94]

I've backed out the idle screw it's about 2 to 2 1/2 turn from bottom still hasn't changed. What do you mean by speed?? I'm pretty sure it's running on all cylinders it's sounds great idling

 

[jimmbo]

Idle speed setting. You said you backed out the idle screw out 2 - 2 1/2 turns from bottom. Is that the idle stop screw? Or are you referring to the mixture screws? When you are setting/adjust the idle stop screw, the throttle cable has to free to move, so the brass barrel mentioned in post #9 has to be out of its holder, and the linkage pushed back against the stop. Once the speed is correct(idling in forward gear) the brass barrel is adjusted so a slight preload is pushing on the throttle stop. Those inline sixes are smooth, and often a non-firing clyinder is not noticed at very low speeds.
Do you have a Service Manual for that engine? Mercury manuals are the best but...
http://www.boatinfo.no/lib/mercury/m...40-115.html#/0

 

[DylRod94]

The mixture screw is which I'm referring to. I'm sure it's a simple mistake I'm overlooking. I'm a rookie when it comes to boat engines especially one this old. Everyone on this forum have been very helpful though

 

[racerone]

The lever on the right is for throttle in nuetral.----Used for starting / warm up of the motor.----The big one on the left is shift for the first part of the motion and as you move it further it applies throttle.------If the small lever moves when you shift there is something wrong in the box !!-----Small things need to be understood and corrected first.-----You can not expect an old motor to run like the new automobiles where all you do is push a button !

 

[jimmbo]

There are 3 carbs, and therefore 3 idle mixture screws. Any idea if the previous owner cleaned and rebuilt the carbs? I'm beginning to think they are in need of a thorough cleaning and refreshing. Removing spark plugs and pouring gas-oil into the cylinders is not a standard starting procedure.
Did you have the engine inspected by a dealer before purchase? If so, do you have any info like compression numbers?
If not, then a compression test should be a priority

 

[DylRod94]

Carbs are freshly rebuilt by myself. Following factory specs in the float chamber. Also compression test showed 115 in all cylinders. When in neutral it'll only idle with idle lever all the way forward when I try to lower it dies before it's pulled down. In neutral with the idle lever all the way forward it idles around 1200-1300 rpm. I believe it's just a simple adjustment problem but I'm just not getting clear instructions on how to adjust #1 the idle mixture screw, #2 I did a Link and sync with the carbs so I believe it's good. Also when the gear shift moves forward I can push it all the way forward with no change in rpms. When put in reverse the throttle works as it should increasing the rpms

 

[DylRod94]

And it starts up a lot easier now. I guess were it he sit awhile the reeds were pretty dry but after a day or two of starting it and letting it idle it starts up after about 10 seconds now

 

[jimmbo]

2 on setting idle mix
http://www.boatinfo.no/lib/mercury/m...0-115.html#/16
http://www.boatinfo.no/lib/mercury/m...-115.html#/116

Float lever setting
http://www.boatinfo.no/lib/mercury/m...-115.html#/112

The throttle not advancing in forward, but advances in reverse. It sounds like there is something wrong in the control box
http://www.boatinfo.no/lib/mercury/m...-115.html#/310

 

[racerone]

There is no change in the operation of reed valves , wet or " dry "-------Have you confirmed that the belt timing is correct ?-----Have you confimed that you have spark that will jump a gap of 3/8" on all 6 leads ?---When motor is running pull one sparkplug lead off at a time.---Does the motor respond the same way on all six cylinders ??------Any pictures of this motor ?