Fuel dumping in 5.0 cobra 1994 mechanical pump, not electric.

Scott Danforth

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saddle816

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$79 for the ford pump the GM ones are under $50
Yes, I purchased that pump on eBay. Won’t fit without making new fuel lines, cant just turn the in and outlet around either. Rubber hoses on a boat kinda bother me when original was a metal line. is this common practice to just fabricate something to fit on a boat .
 

Scott Danforth

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Unbolt the two halves and re-clock the bottom

Or just get a diaphragm kit for your old pump
 

saddle816

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Unbolt the two halves and re-clock the bottom

Or just get a diaphragm kit for your old pump
bolt patter won’t line up, couldnt reclock the two halves. I did try but They can’t be reclocked in any direction. couldn’t find a diaphragm kit either for the old pump I have. But this is all redundant now as I have the only pump that is correct application Without modifying lines.
 

Scott Danforth

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Did you test fuel pressure yet. Should be between 2 and 7psi
 

saddle816

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Sorry, had a little family matter arise haven’t been able to get back to the boat for a little while anyways, fuel pump pressure is about 6 to 7 pounds. Seems to start OK at this point but doesn’t really run that great. Moving onto a whole different thing now I installed a per Tronics 1589 pick up in the distributor ( no spark) pickup was bad. now there is spark. and I changed the coil got it off of Amazon, I guess now I had to cut the resistor wire off According to the directions with the coil so that 12 V will be at the coil always. Read that changing spark plugs to a 50 gap instead of the 32 gap in it now Will help. Does anyone know what spark plugs you have changed to? If you’ve done this coil change or do I just take the old plugs out and gap them up to 50 instead of 32 of course using Motorcraft Ford plugs. Hopefully this is all not too confusing.
 
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alldodge

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Don't change plug heat range nor gap. Increasing gap will cause fuel to burn faster. If it burns faster then preignition can happen. Preignition will destroy your motor pretty quick
 

saddle816

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Don't change plug heat range nor gap. Increasing gap will cause fuel to burn faster. If it burns faster then preignition can happen. Preignition will destroy your motor pretty quick
I’m guessing you’re not familiar with coils and this modification Due to lack of old parts not being made any longer. The coil apparently over heats if gap is not enlarged. It’s a common thing to change plugs depending on the coil I’m reading. Hotter coils 40,000 volts need bigger gaps. Seems to make sense I was looking for the plug and gap info.
 

matt167

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I’m guessing you’re not familiar with coils and this modification Due to lack of old parts not being made any longer. The coil apparently over heats if gap is not enlarged. It’s a common thing to change plugs depending on the coil I’m reading. Hotter coils 40,000 volts need bigger gaps. Seems to make sense I was looking for the plug and gap info.
It’s a pretty common thing to do in an old auto engine.. but a boat engine is climbing a hill all the time. Under a complete load at all times in other words.. you don’t want to run on the raggedy edge with a boat. A hotter coil doesn’t ‘need’ a bigger gap, the plug gets an arc, the energy not used is wasted.Electricity will only draw what it uses. It won’t draw extra, just because. More goes on in the combustion chamber than you may understand, and at 100% duty cycle, any shortcomings will be found quickly. Pre ignition is a very common problem with marine engines
 

saddle816

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It’s a pretty common thing to do in an old auto engine.. but a boat engine is climbing a hill all the time. Under a complete load at all times in other words.. you don’t want to run on the raggedy edge with a boat. A hotter coil doesn’t ‘need’ a bigger gap, the plug gets an arc, the energy not used is wasted.Electricity will only draw what it uses. It won’t draw extra, just because. More goes on in the combustion chamber than you may understand, and at 100% duty cycle, any shortcomings will be found quickly. Pre ignition is a very common problem with marine engines
Ok sounds good, I’ll stick with same old plugs. I’m sure that’s my problem, boat guys here, car guys are my only source. Car guys say gaps used to be in the 30s because coils were not nearly as hot as old days. Thus gaps have gotten bigger with fuel injection and hei ignition Over the years. Old point systems had capacitors to dissipate energy not used. So when car guys say need bigger gaps with hotter coils then it makes Perfect sense to me, but you are saying because of a boat. I do not need to worry about the gap in the plugs going from 32. Let’s say 45-ish. Correct ? Just trying to fully understand boat logic as different from auto logic ? Thanks for taking the time.
 
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matt167

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Ok sounds good, I’ll stick with same old plugs. I’m sure that’s my problem, boat guys here, car guys are my only source. Car guys say gaps used to be in the 30s because coils were not nearly as hot as old days. Thus gaps have gotten bigger with fuel injection and hei ignition Over the years. Old pint systems had capacitors to dissipate energy not used. So when car guys say need bigger gaps with hotter coils then it makes Perfect sense to me, but you are saying because of a boat. I do not need to worry about the gap in the plugs going from 32. Let’s say 45-ish. Correct ?
Just leave the gap and plugs at spec. Which if it’s 32, then run that. The flame front in the chamber is right with those timings. Points in boats were common far longer than autos and the reason is reliability
 

Scott Danforth

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Ok sounds good, I’ll stick with same old plugs. I’m sure that’s my problem, boat guys here, car guys are my only source. Car guys say gaps used to be in the 30s because coils were not nearly as hot as old days. Thus gaps have gotten bigger with fuel injection and hei ignition Over the years. Old point systems had capacitors to dissipate energy not used. So when car guys say need bigger gaps with hotter coils then it makes Perfect sense to me, but you are saying because of a boat. I do not need to worry about the gap in the plugs going from 32. Let’s say 45-ish. Correct ? Just trying to fully understand boat logic as different from auto logic ? Thanks for taking the time.
actually, gaps got bigger to ignite leaner mixes to pass emissions. combustion chamber design and shape determines speed of flame propagation needed. that in turn determines which gap is needed to balance nox, power, detonation based on fuel BTU, compression ratio, etc.
 

saddle816

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actually, gaps got bigger to ignite leaner mixes to pass emissions. combustion chamber design and shape determines speed of flame propagation needed. that in turn determines which gap is needed to balance nox, power, detonation based on fuel BTU, compression ratio, etc.
Sounds good, will see what happens
 

saddle816

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Just leave the gap and plugs at spec. Which if it’s 32, then run that. The flame front in the chamber is right with those timings. Points in boats were common far longer than autos and the reason is reliability
uuuhhh.... most marine ignition systems stock run more than 40KV. no need to change spark plug gap
Just leave the gap and plugs at spec. Which if it’s 32, then run that. The flame front in the chamber is right with those timings. Points in boats were common far longer than autos and the reason is reliability
I don’t have points ? Also plug number in old owners man isnt available on Amazon what plug do people use in this engine. 302 Ford ? Any ideas ? Thanks for input
 
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saddle816

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uuuhhh.... most marine ignition systems stock run more than 40KV. no need to change spark plug gap
in 1994 ford cobra seaswirl omc 40,000 v really. Was told they were less in the old days…lol I’m getting so much info. Glad I’m getting so much different info here in the boating world.
 

saddle816

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any ideas about what spark plugs to use ? 1994 302 ford cobra 2 barrel engine ? The ones in my old owners manual dont seem to exist on Amazon. Must have been a number change somewhere in the past. Thanks to anyone with this info.
 

Scott Danforth

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any ideas about what spark plugs to use ? 1994 302 ford cobra 2 barrel engine ? The ones in my old owners manual dont seem to exist on Amazon. Must have been a number change somewhere in the past. Thanks to anyone with this info.
go to napa with the number from your manual.
 

saddle816

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go to napa with the number from your manual.
Thanks, just thought the people here would have the info. Trusting parts guys is usually a mistake. As I’m finding out boats and cars are much different. Will start at the auto parts place I guess then.
 
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