Mercruiser 470 choke staying open after warmed

[tinydog]

just purchased this boat and learning as I go but made the mistake of starting off with a car motor train of thought when purchasing a boat with the Mercruiser 470 engine and have only run it on muffs a few times and every time after it warmed up and I let it cool before cranking again it wouldnt start and I would pull the arrestor and find the idle screw holding the choke open so I started popping the throttle once before trying to start it to let it close and if I loosen the idle screw enough to let it close on its own of course the idle is to slow to run. Is this normal or is there something I need to be looking at ??

 

[Bondo]

Re: Mercruiser 470 choke staying open after warmed

Is this normal or

Ayuh,.... just pump the throttle Once....

 

[nola mike]

Re: Mercruiser 470 choke staying open after warmed

Normal behavior. Pumping the throttle closes the choke. When the ignition is left on, it warms a coil/opens the choke. Pump it once to reset the choke, start in neutral with the throttle open halfway or so.

 

[tinydog]

Re: Mercruiser 470 choke staying open after warmed

This is a 1986 Wellcraft American 190 and I see no way to control the throttle other than moving it forward which engages the leg. Am I missing something ? thanks

 

[Bondo]

Re: Mercruiser 470 choke staying open after warmed

This is a 1986 Wellcraft American 190 and I see no way to control the throttle other than moving it forward which engages the leg. Am I missing something ? thanks

Ayuh,...Usually there's a Button to push, or pull for neutral, or ya push in on, or pull out on the lever to engage it....

 

[tinydog]

Re: Mercruiser 470 choke staying open after warmed

Went and looked the only button I see is the one on the under side of the shift handle that I have to push in to move the shifter out of the neutral forward.

 

[Bondo]

Re: Mercruiser 470 choke staying open after warmed

Ayuh,... time for a Picture I guess...

 

[Don S]

Re: Mercruiser 470 choke staying open after warmed

Even a small blurry picture will give us a hint of what kind of control you have.

Here is how to easily post a picture http://forums.iboats.com/showthread.php?t=468676

 

[tinydog]

Re: Mercruiser 470 choke staying open after warmed

Here is the pic of the throttle I have

 

[EddiePetty]

Re: Mercruiser 470 choke staying open after warmed

"....This is a 1986 Wellcraft American 190 ...."

Ijust finished repairing an '85 American. To release the drive selection and have throttle only: Place the selector in neutral, grasp the lever at the base and pull outward (to port)

 

[tinydog]

Re: Mercruiser 470 choke staying open after warmed

cool thanks ive learned something i will definitly try that thanks

 

[Don S]

Re: Mercruiser 470 choke staying open after warmed

That's why pictures are important with controls. That isn't even a Mercruiser control. Just the ones Wellcraft and several other manufacturers used instead of using OEM

 

[riskibusiness]

Re: Mercruiser 470 choke staying open after warmed

that picture is pretty blurry but isnt there a push button right in the middle of the pivot point of the base?

 

[mpdive]

Re: Mercruiser 470 choke staying open after warmed

Now I'm really confused......Since when does a marine carb have a fast idle cam? Seems that's an accident waiting to happen..... How can an idle screw have any correlation to a choke coil? I'm doubly confused...

 

[nola mike]

Re: Mercruiser 470 choke staying open after warmed

It doesn't. The cam sets the choke.

 

[mpdive]

Re: Mercruiser 470 choke staying open after warmed

It doesn't. The cam sets the choke.

What cam? I have rebuilt tons of marine carbs and none have had a choke cam, or fast idle cam. It would be plain dangerous in a marine setting. The choke is entirely independent of any throttle linkage and consists of nothing more than a choke coil and linkage to the butterfly. If they had cams it would be very easy to put a boat in gear at 1500 rpm's and take out everybody at the dock. Are we mistaking an auto carb for a marine on this boat? Just asking.......

 

[nola mike]

Re: Mercruiser 470 choke staying open after warmed

No, there's a cam, and the throttle linkage is indeed connected to the choke. It's only to hold the choke closed initially. The cam doesn't affect the throttle butterflies.

 

[nola mike]

Re: Mercruiser 470 choke staying open after warmed

Don't know where the pic went.

 

[mpdive]

Re: Mercruiser 470 choke staying open after warmed

I didn't realize you were referring to the follower cam Mike. My apologies. When the OP referred to backing off the screw for the idle, I'm thinking it's the fast idle cam screw which I never saw before.

 

[vincechig1975]

Re: Mercruiser 470 choke staying open after warmed

the linkage on the right side of the carb is for choke the one to the left is for throttle, this is a mercarb , I have one and finished rebuilding it on my 470, lemme ask this on the other side of this does it have the electronic choke control like you would find on a gm rochester ....?
Would you be able to take a photo of the other side of this for us to take a look see....
That screw is located on that same side as the linkages and on the lower part, i believe in between the throttle and choke but it's in there it's the only one there....sorry it's forward of the choke linkage just to the right check it out. Check to see what's causing it to stay it might be that those linkages need a bit of adjustment (bending) but be careful they only bend so far and so many times, I had to do this with mine but it might not be that in your case just check it out. I came up with this one and it worked for me. The
screw is the idle screw , the fuel adjustment screw is in the rear of this carb, on the base and it only has one. This is one of the differences between the Rochester and the Mercarb, they ask you these things to double check prior to purchasing a carb kit. The other thing I checked was the function of the choke thermostat while off the carb and while on it to see it's operation and if there were any issues, binding etc....it wasn't the choke's fault it was binding....it was the linkages once i adjusted them it works fine now.