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Help please choke

P

pullenpoynt

Member
i have a 1974 srv190 -with a 3

i have a 1974 srv190 -with a 302 ford 188hp and 2bbl rochester -
have been having problems with choke since i bought the boat last year - usually to start i double pump the throttle - this year i don't plan to do that

seems the choke isn't closing when i turn the key to run position

in the on position the wiring to the choke gets very warm - i've traced the wiring and found that one wire comes from the run position on ign switch and one comes from the coil + side

i 've cut the wire from the switch and left the +side from the coil connected and the wiring doesn't get hot
but the choke still is inop

where do i turn ?


thanks
bob
 
"Robert: What do you think Gu

"Robert: What do you think Guys?

It sounds like your electric choke is due for replacement. The choke has an electric heater wrapped by a bi-metal coil that expands when heated and opens the choke while the ignition switch is on. The choke then contracts to shut the butterfly when cold. The butterfly or choke should close to a point where you can just fit a 1/8th" drill bit between the choke and the airhorn.

You can try to adjust the choke by loosening the three screws on the choke housing and rotating it slowly until the choke closes all but 1/8". It is only a temporary repair. Order a new choke to install when this temporary fix no longer works.

Concerning the hot wire issue; "one wire comes from the run position on ignition switch and one comes from the coil + side". The choke sounds to me that it is wired wrong. Is the electric choke on your engine a changeover from an exhaust stovepipe heated choke?

The choke needs 12 VDC from an ingition switch source to the choke, usually a purple wire, and a ground wire (black)from the block to one of the choke mounting screws. Connecting the coil + terminal to the choke just isn't kosher. If you are running a points dist., the voltage from the coil is less than 12 VDC. Your choke has been cooked.

Connecting one side of the choke to the + side of the coil and the other to an ignition wire is not right. This incorrect setup is probably causing your hot wires. What color are the wires?

Your boat is a 1974 and most likely has several wires that are corroding inside the insulation. If you peel back the insulation and find the copper wire is no longer shiny but is dark brown or somewhat blackened, replace the length of wire since it could result in an electrical fire.

Before adding a connector on the wire end, tin the wire with rosin core solder and cut to length first. Tinning helps prevent corrosion. Wherever you make the splice on the other end, twist a 1/2" section of bare clean wire together, add flux and solder the joint. Don't forget to slip on a 2" length of shrink tubing on the wire before twisting. Keep the tubing away from heat since it shrinks quickly. When the joint is cool, slip the tubing over it and apply heat from a hair dryer on low fan/heat or a Bic lighter until it shrinks.

SAFETY FIRST!!!!! MAKE DARN SURE THE BILGE IS WELL VENTILATED AND YOU ARE NOT WORKING AROUND A LEAKING OR OPEN FILLER TANK WITH FUEL FUMES!!!!! HAVE AN EXPERIENCED HELPER THAT IS KNOWLEDGEABLE AND READY TO DOUSE YOU WITH A WORKING FIRE EXTINGUISHER IN HAND JUST IN CASE. Guy"
 
thanks guy

the wiring looks

thanks guy

the wiring looks original as i peeled back the harness - i couldn't find a purple wire anyplace near or close to the carb - the wires running from the choke are white from the ign switch and tan from the coil and also a black ground wire attached to a screw on the choke housing

i have no way of knowing wheter it had a previous stove choke as i got this boat last year
and with it the problems

so essentially your saying that because the thermostatic elec choke might be fried it may be causing an overload of resistance thus causing the wires to become hot

the seloc book i have shows the wiring as described and says the tan wire is a resistance wire ?- i just ordered the merc book for this year model - but in the meantime any and all help is appreciated

you said the the choke needs a 12v supply from the ign switch - and the coil wire is not needed

wouldn't that setup keep a constant power to the choke thus keeping it always closed

i thought the choke only needed to close during starting
 
"Robert: I don't have the

"Robert: I don't have the year manual you have so I was going on the premise it is similar to my 1987 mercruiser. The wiring is correct per your manual.

You can tell if you had a stove pipe choke by looking at the intake manifold directly under the choke. There will be either a flat oval shaped cover plate and/or one with two pinched tubes, hence stove pipes that drew heat from the exhaust crossover inside the intake manifold.


The white wire supplies the 12 VDC to the choke continuously with the ignition on. Are the white and tan wires connected at the choke? Are you running a points and condenser ignition? I believe you are since the tan wire is a resistance wire that would drop the voltage from the 12 VDC at the choke to 6 VDC at the coil. Are the points fried? See your manual. If so, replace them along with a set of plugs and set them and the timing to specs. Check the cap and rotor for corrosion and replace per the manual description.

NOTE: I would get rid of the points with an electronic conversion kit, about $50. IF YOU DO THAT, YOU MUST REPLACE THE TAN WIRE WITH A NON-RESISTANCE WIRE TO GET A FULL 12 VDC TO THE COIL.

By cutting the white wire, you don't have power to the choke or the coil--it will never start if the white and tan wires were connected in series. Reconnect the wires as they were and measure the voltage at the choke with the ignition on.

You should have 12 to 14 VDC with a fully charged battery, measure the voltage of the battery and write it down for reference. Now check the voltage at the ignition switch RED wire. It should read almost the same as the battery, less up to 1 volt. If the RED wire reads 12 to 14 VDC with the switch in the run position, then the white wire should read exactly the same. DISCONNECT THE BATTERY GROUND WIRE FOR THIS SERVICE. If the white wire reads less than the RED wire, remove and clean the red and white wire terminal ends and the switch terminals with fine sand paper and reconnect to retest. RECONNECT THE GROUND ON THE BATTERY. If the voltage reading on the white wire is not the same as the red wire, replace the ignition switch.

If all the voltages are good, adjust the choke while COLD as I stated earlier, make sure it moves freely. If not, squirt some penetrating oil on the shaft ends, remove the choke and see if it loosens. If the butterfly moves freely without the choke, the shaft is good. If you reattach the choke and it binds again, replace the choke and adjust it to specs.

Before starting the engine, hold the choke open while cold with the ignition off and pump the throttle with one long continuos stroke and see if you have fuel squirting in the air horn like a double barrelled squirt gun. If you see the squirt fuel, your accelerator pump is working. Now see if it will start. MAKE SURE THERE IS WATER RUNNING FROM A HOSE TO THE INLET MUFFS OR YOU WILL COOK THE IMPELLLER IN THE OD.
Guy"
 
"guy
thanks for helping
i ha

"guy
thanks for helping
i have an electronic conversion in the dist, as well as new cap ,rotor plugs, and wires -
the wht wire i cut - i guess ran to the choke and the tan wire came from the coil to the choke both wires wht+tan were connected to the choke and in this set up they got hot -

with the wht cut - and ign switch turned to run the tan wire send juice to the choke - however- it is not a constant as when the white wire was connected

i guess i need to know if or how this system operates - if the 12v white wire keeps the choke always energized and the tan wire from the coil adds current to close the choke"
 
"Robert:

When the ignitio

"Robert:

When the ignition switch is in the run position, the white wire supplies 12 VDC to energize the choke's electric heater. When the engine had a points and condenser ignition, the tan wire was used to provide enough resistance to reduce the 12 VDC to 6 VDC for the points, coil etc. to operate at a lower voltage. Do you know what the voltage is supposed to be at the coil for the electronic ignition? What is the make and model of the electronic ignition? Was it put on recently?

Did you perform the voltage checks I suggested? They will provide you the data to determine if the switch and white wire are working properly.
Make sure the ground wire on the choke reads "0 ohms to ground". A poor ground causes all sorts of current flow problems including overheating wires.

How about the choke adjustment? The white wire is needed to energize the choke. Will the engine start without it? I bet it won't produce a spark at the plugs without it unless the installer used an alternate 12 VDC source.

Guy"
 
hello guy
sorry for seeming

hello guy
sorry for seeming so dense - but i think i get it
the choke is suppose to be normally closed - cold- and when the ign switch is turned on 12v come from the white wire to energize the the opening of the choke as the bimetal thermal strip expands - the choke opens -
the tan wire feeds the points coming from the choke as a relay source of power and since the system was changed over to whatever electronic the resistance in the tan wire is to low to handle the 12v - thus the wire gets hot - so i need to replace the tan wire with a bigger gauge wire able to handle 12v - correct
 
"Robert:

I would not remo

"Robert:

I would not remove the TAN wire yet. You need to measure the voltage first at the choke and at the coil. Are they the same or are they different? If the voltage is the same 12 VDC, there is no need to change the tan wire.

If the voltage is different, the difference may be normal for the electronic conversion. That has to be determined yet. If the spark from the coil is sufficient to run the engine--leave it alone.

The CHOKE seems to be the problem here. Either it is the cause of the hot white wire or the white wire is the source of the problem or somewhere from the choke back to the ignition switch. You have to check the voltage and get another choke since it seems to be worn out.
Guy"
 
guy
i put a new choke element

guy
i put a new choke element in and the problem cleared up - evidently - it was fried and causing the wires to over heat - i guess - as now everything is running cool - thanks for your help with this -

bob
 
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