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Discussion Starter #1
I recently acquired a 1977 Cougar Xr7 with a 351m. I drove it around town and it died after about 30min. No chugging or sputtering, just like someone turned the key off. It would crank just fine but no start. Battery died trying to get home. Got a jump after 20min and it started right up and made it the 5min home without issue.
Gave it a mild tuneup. New plugs, wires, rotor, cap, coil, ignition control module. Ran good and gave it another go. Same thing....30ish min into driving it just shut off again. This time though it would crank, fire, run for 2sec and die. Once again like someone turns the key off. I got a jump again after 20min, even though it was still cranking. It started up and stayed running if I held the choke closed and slowly let it open manually after firing. Drove 20min home without issue. It must
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be electrical?....but what? Regulator??
 

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I would also change the fuel filter and check the air filter.
 

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Discussion Starter #3
Okay I just tried again today and it is definitely fuel related. I have a new regulator installed now as well and it did it again. When the temp gauge reads halfway it chugged and died. It does have a new sending unit. If I force the choke closed it will run but rough. As soon as I let the choke open it dies. After letting it cool down for 20min it starts right up and I can drive again for 20min. So it seems to be going way lean when warm? While cranking after it dies smoke will push out of the valve cover breather. So am I actually overheating even though gauge says different? I topped off the coolant prior to driving and nothing pushed into the overflow though. It does have a new air filter...new fuel sending unit as well. I did not see an in-line fuel filter.
 

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IIRC the 1977 has the fuel filter screwed into the carb. It should look like this

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Discussion Starter #6
Thanks for the suggestions! I will try that and check out the filter. I am guessing the previous owner had some issues to but didnt say anything. There is a new fuel pump installed and a new section of rubber hose from steel line after pump. The last 6-8 inches are now rubber.
 

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Discussion Starter #7
Okay so I just ran it in the garage again until it reached that temp and it died again. Cracked the fuel cap and I didnt hear anything. It did start up again this time though. I didnt run it again long just in case. The radiator hoses feel hot, radiator cap feels hot so it is circulating coolant through the radiator. No boiling noises at all. I'll attach 2 pics of the temp gauge...one while running as it started to chug and die, and the other after I turned the key back on to accessory.

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Discussion Starter #9
I would think fuel supply is the issue. If I have someone crank it over and I hold the choke closed it will fire and run...poorly but will run. If I let go it dies instantly. So I'm thinking it is a lean situation??
 

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Check where the fuel lines are routed near heat sources, you have the symptoms of vapor lock. I have covered fuel lines with foil and problem stopped.
 

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Discussion Starter #11
After doing a lot of reading last night I think it is a vapor lock type situation like suggested. I looked over the fuel line routing closer this morning and the section of steel line from the pump to the 6 inches of rubber before the carb is literally touching the face of the head and top of the water pump. Think that may be a good place to start......
 

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test your fuel pressure .. watch it as you let it run and see if it drops off.. I'm betting on restricted fuel lines... weak fuel pump and or fuel filer being plugged.. I'd start with when it dies.. with your air cleaned off .. pump ... carefully looking in the carburetor and pump the throttle and see if it squirts.
 

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Discussion Starter #13
I am going to order a new fuel filter either way, local parts store doesnt have any in stock....figures lol. I didnt have time to mess with it today at all...fixing my tractor. I do believe you are right with low fuel flow. I didnt look down the carb last time, but after it did die, and I got it to restart it sounded different in the carb. It didnt have a steady sucking sound. It had what I could only describe as the sound of a garden hose with a kink in it. The sputtering sound. I looked at the fuel pump, it looks new...and there was the empty box in the trunk from the previous owner. So I guess I can change the filter first, replace the steel line and re-route away from engine, and last resort add an inline electric pump??
Thanks again for the help!!!
 

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you can also remove the line that goes from the gas tank to the fuel pump at the fuel pump ... and with low pressure compressed air ( 20 psi should do it) remove the gas cap and back blow the fuel line ...
 

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Discussion Starter #15
Went through a half tank today driving it around. That felt so good to do. I know the air temp was cooler today, but engine still got to temp fine. I changed the fuel filter as suggested, put an insulated sleeve on the fuel line, adjusted the routing to make sure it doesnt contact the engine, and have a vented gas cap now. No issues at all today!
 
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