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john jones
09-28-2012, 12:54 AM
my electric choke isn't working. I tried to adjust it and it doens't even move the butterfly when I turn it. I suspect the spring inside the choke cap is bad.

I have a 1993 Maristar with 351. It has dual fuel lines running to it. Which carb do I have on my boat?

Is there a difference between marine and non-marine choke caps?

kjohnson
09-28-2012, 08:07 AM
You can order a new electric choke from Discount Inboard Marine.

JimN
09-28-2012, 08:39 AM
my electric choke isn't working. I tried to adjust it and it doens't even move the butterfly when I turn it. I suspect the spring inside the choke cap is bad.

I have a 1993 Maristar with 351. It has dual fuel lines running to it. Which carb do I have on my boat?

Is there a difference between marine and non-marine choke caps?

They get rusty. Remove the choke heater and take it to an auto parts store. Other than the starter or alternator, you don't need to buy engine parts from SkiDim and even those can be sourced locally- the rest are car parts.

thatsmrmastercraft
09-28-2012, 08:59 AM
You might want to verify that you have power running to the choke cap before replacing it.

dpcsar
09-28-2012, 11:37 AM
They get rusty. Remove the choke heater and take it to an auto parts store. Other than the starter or alternator, you don't need to buy engine parts from SkiDim and even those can be sourced locally- the rest are car parts.

I would add the carburetor to the list of "needed" marine parts. An auto carburetor links the choke to the throttle. When it's cold it revs at a higher RPM until warm.

The starter, you can use an auto and seal it with silicon. Since we are talking about a Indmar 351w. You want a 68' mustang automatic starter. The '68 manual is short and the teeth only engage 1/4 of the way. (stripped the teeth on a flywheel that way.:mad: $50 repair if you take the flywheel off yourself :)).

JimN
09-28-2012, 11:43 AM
I would add the carburetor to the list of "needed" marine parts. An auto carburetor links the choke to the throttle. When it's cold it revs at a higher RPM until warm.

The starter, you can use an auto and seal it with silicon. Since we are talking about a Indmar 351w. You want a 68' mustang automatic starter. The '68 manual is short and the teeth only engage 1/4 of the way. (stripped the teeth on a flywheel that way.:mad: $50 repair if you take the flywheel off yourself :)).

I was referring to electrical parts that could produce spark, which must be contained in the motor, not with linkage or other mechanical aspects. However, older carbs don't always use the linkage in this way. Some use the old-style choke thermostat that was heated by the intake manifold, like what they had in the '60s. I have a friend with two Carver boats and the one with GM engines has/needs new heaters.

dpcsar
09-28-2012, 11:46 AM
my electric choke isn't working. I tried to adjust it and it doens't even move the butterfly when I turn it. I suspect the spring inside the choke cap is bad.

I have a 1993 Maristar with 351. It has dual fuel lines running to it. Which carb do I have on my boat?

Is there a difference between marine and non-marine choke caps?

I am guessing that you have a Holley. There should be some markings on it. I have a Holley on my '89 351w. I also have a completely rebuilt spare for sell.

Have you tried running it with the choke all the way open? A shop turned my completely open. I adjusted it according to Holley. I didn't notice a difference.

The operation of the choke on a Holley marine carburetor is to open when power is supplied to the choke. You supply power when you turn on your key. So, if you turn on the key and don't start the engine right away, you basically render the choke useless. That is why when warming the engine you usually have to use the throttle. On an auto carburetor the choke is connected to the throttle, but not on a marine carburetor.

dpcsar
09-28-2012, 11:48 AM
I was referring to electrical parts that could produce spark, which must be contained in the motor, not with linkage or other mechanical aspects. However, older carbs don't always use the linkage in this way. Some use the old-style choke thermostat that was heated by the intake manifold, like what they had in the '60s. I have a friend with two Carver boats and the one with GM engines has/needs new heaters.

I agree with you. I also forgot about the distributor. That should be marine also. ;)

thatsmrmastercraft
09-28-2012, 11:57 AM
my electric choke isn't working. I tried to adjust it and it doens't even move the butterfly when I turn it. I suspect the spring inside the choke cap is bad.

I have a 1993 Maristar with 351. It has dual fuel lines running to it. Which carb do I have on my boat?

Is there a difference between marine and non-marine choke caps?

I just re-read this post. You need to take the cap off and re-install it with the end of the spring fitting into the choke lever. Yours is not connected properly, that is why when you turn it, nothing happens.

JimN
09-28-2012, 11:59 AM
I agree with you. I also forgot about the distributor. That should be marine also. ;)

The alternator is another. Any motor without some kind of spark/flame arrestor is forbidden.

JimN
09-28-2012, 12:04 PM
I am guessing that you have a Holley. There should be some markings on it. I have a Holley on my '89 351w. I also have a completely rebuilt spare for sell.

Have you tried running it with the choke all the way open? A shop turned my completely open. I adjusted it according to Holley. I didn't notice a difference.

The operation of the choke on a Holley marine carburetor is to open when power is supplied to the choke. You supply power when you turn on your key. So, if you turn on the key and don't start the engine right away, you basically render the choke useless. That is why when warming the engine you usually have to use the throttle. On an auto carburetor the choke is connected to the throttle, but not on a marine carburetor.

It should be closed when the engine is cold (whether it automatically closes or snaps shut when the throttle is moved before cranking), then it opens gradually as the engine and thermostat become warmer. If the choke is open and the engine is cold, it will be too lean and may bog or just not start easily. If the engine was cold when you ran yours with the choke open, it should have run like crap unless it was set for a rich idle mixture.

dpcsar
09-28-2012, 12:49 PM
It should be closed when the engine is cold (whether it automatically closes or snaps shut when the throttle is moved before cranking), then it opens gradually as the engine and thermostat become warmer. If the choke is open and the engine is cold, it will be too lean and may bog or just not start easily. If the engine was cold when you ran yours with the choke open, it should have run like crap unless it was set for a rich idle mixture.

I thought as you until I did some research. The only thing changing the choke is electricity, which is supplied by the key being on. It will open all the way with a cold engine. That is how the Holley marine carburetors work. I don't know about others.

I had a 351w rebuilt to a 393 and the re-builder told me the 600 CFM carburetor wasn't enough. I replaced it with a 750 CFM carburetor so the motor wouldn't be to lean. I had a distributor points problem, which I thought was the carburetor (engine ran like crap all the time). So I ended up doing a lot of research on the carburetor. I called Holley and asked about the choke operation and why it was not opening the throttle when cold. For a Holley automotive carburetor, you are correct, the choke controls the throttle, and there is electricity and hot air controlling the choke. For a marine carburetor, it is only electricity.

You can check it out. Turn your key on and check it 5-10 minutes later. The choke will be all the way open and the engine will be cold.

JimN
09-28-2012, 02:58 PM
I thought as you until I did some research. The only thing changing the choke is electricity, which is supplied by the key being on. It will open all the way with a cold engine. That is how the Holley marine carburetors work. I don't know about others.

I had a 351w rebuilt to a 393 and the re-builder told me the 600 CFM carburetor wasn't enough. I replaced it with a 750 CFM carburetor so the motor wouldn't be to lean. I had a distributor points problem, which I thought was the carburetor (engine ran like crap all the time). So I ended up doing a lot of research on the carburetor. I called Holley and asked about the choke operation and why it was not opening the throttle when cold. For a Holley automotive carburetor, you are correct, the choke controls the throttle, and there is electricity and hot air controlling the choke. For a marine carburetor, it is only electricity.

You can check it out. Turn your key on and check it 5-10 minutes later. The choke will be all the way open and the engine will be cold.

The choke needs to be closed when the engine is cold and the only thing changing the choke's position on a choke thermostat is heat, regardless of whether it's operated electrically or uses the heat from the intake manifold.

The choke only allows the amount of air to vary with the choke thermostat's temperature, if it has one- it doesn't control the throttle. If the thermostat is missing/inop, the throttle will have to be pumped several times when cold, in order for the engine to start unless the air is at the correct temperature by coincidence. The throttle cable does that, although the throttle can affect the choke if the carb has the appropriate linkage. If the throttle wasn't the main priority and the choke would control the engine, it would be possible for the engine speed to experience runaway because the choke would be controlling the engine. Electric choke isn't on ALL marine carbs and if I go out on my friends' boat this weekend, I'll shoot photos of the carbs with the thermostats on the intake manifolds. The electric choke thermostat is only on the boats that were spec'd that way, or the ones where it was added. It's not a requirement, but it works better than the latter because the coolant is usually fresh water, which is colder than coolant unless the boat is operated on extremely cold bodies of water. The service manuals I have read show that the choke should close to about 5/16" when cold, then open fully at normal operating temperature.

The problem with an electric choke is that the engine may still be running at an extremely low temperature and the heated coil will still open the choke fully, just because it was hot enough to open it fully, with no input from the engine. In your advice to turn the key to ON and wait, that's exactly what I'm referring to- the engine will be hard to start if the coolant temperature is low because it needs to be choked (low temperature air contains more oxygen and that requires either more gas or less air going through the carb) and the thermostat/engine control really needs to have input from the engine in order to operate effectively. The design assumes that the engine will be started soon after turning the key to ON. I don't have any vehicles with a carb, either. The only things that do, are my lawn mower and snow blower and that has a manual choke.

john jones
09-28-2012, 03:42 PM
when I started it last night I had the aircleaner off so I could see the butterfly position. I pumped the throttle twice, butterfly didn't move. I tried to adjust it by rotating the black cap, nothing. I had to let the boat warm up for awhile before I could get it off the trailer.

How do I check for voltage at the choke. I remember there was a purple wire going to the coil and another wire, I can't remember where it went. If I have voltage I suspect the spring is bad inside the choke cap.

After the inital warm up the boat ran great and would restart fine.

j.mccreight@hotmail.com
09-28-2012, 03:57 PM
when I started it last night I had the aircleaner off so I could see the butterfly position. I pumped the throttle twice, butterfly didn't move. I tried to adjust it by rotating the black cap, nothing. I had to let the boat warm up for awhile before I could get it off the trailer.

How do I check for voltage at the choke. I remember there was a purple wire going to the coil and another wire, I can't remember where it went. If I have voltage I suspect the spring is bad inside the choke cap.

After the inital warm up the boat ran great and would restart fine.

purple wire is switched 12v and should feed from the 12v side of the ballast resistor, other wire probably is black and is the ground.

JimN
09-28-2012, 04:41 PM
when I started it last night I had the aircleaner off so I could see the butterfly position. I pumped the throttle twice, butterfly didn't move. I tried to adjust it by rotating the black cap, nothing. I had to let the boat warm up for awhile before I could get it off the trailer.

How do I check for voltage at the choke. I remember there was a purple wire going to the coil and another wire, I can't remember where it went. If I have voltage I suspect the spring is bad inside the choke cap.

After the inital warm up the boat ran great and would restart fine.

The choke is controlled by either the electric choke thermostat or, if it has the appropriate linkage and the heat-activated thermostat (non-electric), the spring action of the thermostat. Since the electric thermostat is supposed to close when it gets cold, you should see a closed thermostat if the temperature warrants it, or somewhat/totally open as the temperature increases. The thermostat doesn't care what makes it hotter, it just reacts to the temperature by opening and closing when the temperature changes.

Remove the cover and thermostat and look at the center- it should have part of the spring going across and this fits into the slot on the shaft for the choke. If this part of the spring is missing, you need a new one.

Here's a bunch of different ones- you should be able to get a good replacement by removing yours and taking it to a parts store.

http://www.carburetor-parts.com/category_s/111.htm

If it only has one wire going to it (purple), look at the thermostat- it may have the other terminal missing and it should look like it has a rivet where the terminal should be, ot a round washer with a rivet. This would indicate that the thermostat grounds internally.

dpcsar
09-28-2012, 06:17 PM
when I started it last night I had the aircleaner off so I could see the butterfly position. I pumped the throttle twice, butterfly didn't move. I tried to adjust it by rotating the black cap, nothing. I had to let the boat warm up for awhile before I could get it off the trailer.

How do I check for voltage at the choke. I remember there was a purple wire going to the coil and another wire, I can't remember where it went. If I have voltage I suspect the spring is bad inside the choke cap.

After the inital warm up the boat ran great and would restart fine.

Do you know if it is a Holley carburetor? I thought all of the ford 351's were Holley carburetors.

From my experience, presuming it is a Holley 4160, your electric choke spring may be disconnected. When you rotate the cap the butterfly should move. Check the spring is connected under the cap.

To check voltage on the Holley: There are to connectors on the choke. One is ground and the other is +12V. You can check it there with the key on.

@JimN - I am presuming 'john jones' has a Holley 4160 marine carburetor. On my boat there isn't anything but electricity controlling the choke. I agree that all boats aren't the same and the operation of the choke is what you describe. I believe that 'john jones' has a ford 351w as he stated a '351'. The Holley carburetors can use ventilation from the value covers to help with the heating of the electric choke, but when I talked to Holley, they said not to use it. The thermostat doesn't do any thing for the Holley carburetor. May be you are thinking about a TBI or MPI system?!?!?! :confused:

JimN
09-28-2012, 08:12 PM
Do you know if it is a Holley carburetor? I thought all of the ford 351's were Holley carburetors.

From my experience, presuming it is a Holley 4160, your electric choke spring may be disconnected. When you rotate the cap the butterfly should move. Check the spring is connected under the cap.

To check voltage on the Holley: There are to connectors on the choke. One is ground and the other is +12V. You can check it there with the key on.

@JimN - I am presuming 'john jones' has a Holley 4160 marine carburetor. On my boat there isn't anything but electricity controlling the choke. I agree that all boats aren't the same and the operation of the choke is what you describe. I believe that 'john jones' has a ford 351w as he stated a '351'. The Holley carburetors can use ventilation from the value covers to help with the heating of the electric choke, but when I talked to Holley, they said not to use it. The thermostat doesn't do any thing for the Holley carburetor. May be you are thinking about a TBI or MPI system?!?!?! :confused:

There's no choke thermostat on an injected engine- the ECT, MAP sensor and ECM are in cahoots and they combine to cause the injectors to open and close at varying lengths of time.

john jones
09-29-2012, 06:55 PM
I pulled it apart today and found that the spring wasn't hooked onto the tit (for lack of a better word)

I cleaned everything, put it all back together. I pumped the throttle twice which closed the butterfly. turned on the ignition, looked at it again about 2 minutes later and the butterfly was fully open!

Thanks again for all the help! I wish my rear main seal leak was going to be this easy:(

JimN
09-29-2012, 07:40 PM
I pulled it apart today and found that the spring wasn't hooked onto the tit (for lack of a better word)

I cleaned everything, put it all back together. I pumped the throttle twice which closed the butterfly. turned on the ignition, looked at it again about 2 minutes later and the butterfly was fully open!

Thanks again for all the help! I wish my rear main seal leak was going to be this easy:(

If we discuss it for a while, maybe it will go away.:D