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Old 07-31-2017, 04:40 PM
Tmac in Folsom Tmac in Folsom is offline
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Cool 85 S&S - sudden loss of power

OK...1st time I've posted here; apologies in advance if this topic has already been covered elsewhere within the site....1985 Stars & Stripes, 351, Power-Slot, 460 Holley, Prestolite Disti with cap & rotor points replacement kit.

I was cruising around on the Sacramento River Delta on Saturday and, after driving for a fairly extended period of time (at least 60 minutes of continuous motor running), I experienced a complete loss of power at which point the engine died. Gas gauge said I had a quarter tank but I pulled off the rear cover none the less for a visual inspection; plenty of fuel. I let the engine sit as I drifted downstream for ~5 minutes and then it started up and ran fine for ~10 minutes until I lost power again...this time it did not completely cut out and I was able to limp to the Marina at 5 mph.

Fuel pump is 1 month old and I'd operated the boat a total of ~3-4 hours on the new pump. Engine temp was nice and low and air temp was ~90 degrees. It's been over 3 years since carb was rebuilt but it starts "fairly" easily and, once the engine has warmed up, idles perfectly. I put a flame thrower coil in the boat ~3 years ago....anybody have any thoughts?
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  #2  
Old 07-31-2017, 04:46 PM
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thatsmrmastercraft thatsmrmastercraft is offline
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Fuel filter comes to mind. How long since you replaced yours? Also thinking the fuel tank vent getting clogged. It's on the top of the transom just below the rub rail. If it gets clogged it will fight your fuel pump and not allow fuel to be pumped out of the tank.
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Old 07-31-2017, 05:08 PM
Tmac in Folsom Tmac in Folsom is offline
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yeah, I thought about the fuel filter and it has been a little while (2-3 years) since I replaced. I'll also check the fuel breather/vent; I keep a pretty close eye on it but maybe a pesky insect has started a nest in there....thank you for your input
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Old 07-31-2017, 05:14 PM
88 PS190 88 PS190 is offline
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I had a bizarre scenario like that where someone had previously bypassed the kill switch and didn't do a good job of connecting the wires. Started doing that suddenly and would be exactly the same hit a bump - comes to a stop then would crank/not start and eventually she'd go and then cut out. Finally wouldn't start and I looked everywhere to fix it. Pushed in on the kill switch button and when holding inwards would run.
Irritated me for a good long time.
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Old 10-14-2017, 06:00 PM
Tmac in Folsom Tmac in Folsom is offline
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OK...it's taken me a while to reply back but here's what I've investigated. 1) made sure the air vent was unobstructed...2) changed fuel filter/water separator...unfortunately, the problem persists. I read a few threads about faulty check valves to I decided 32 years was long enough to wait to swap mine out. I pulled the tank this morning with the intention of replacing the check-valve (anti-siphon valve) and inspecting the fuel tank pick-up tube. It took herculean strength to remove the check-valve from the 90 degree elbow but I got it off.

Here's my question: how do I remove the fuel tank pick-up tube in order to inspect? It "appears" that I have to remove the 90 degree elbow and then remove a rather large nut which appears to somehow adhere the tube to the tank (this is a plastic tank; not a metal tank). Can anybody help me here?
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Old 10-14-2017, 06:45 PM
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thatsmrmastercraft thatsmrmastercraft is offline
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I'm out...I have an aluminum tank. Someone will be along soon enough with the answer.
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$125 LED LIGHT PACKAGE - FREE SHIPPING
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REBUILT COMPLETE MARINE HOLLEY 4160 CARBS
FOR 302, 351 & 454 STARTING AT $425 DELIVERED
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Old 10-14-2017, 06:46 PM
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thatsmrmastercraft thatsmrmastercraft is offline
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Check your fuel line from the tank to the fuel/water separator. Better yet....just replace it. Now is the perfect time.
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$125 LED LIGHT PACKAGE - FREE SHIPPING
REBUILDING HOLLEY MARINE CARBS - $289 DELIVERED
REBUILT COMPLETE MARINE HOLLEY 4160 CARBS
FOR 302, 351 & 454 STARTING AT $425 DELIVERED
Email - [email protected]
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Old 10-14-2017, 07:44 PM
Tmac in Folsom Tmac in Folsom is offline
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did that about 2 years ago.....thanks for your input but I'm 99% certain that NOT the issue. Is it possible that my sudden loss of power could be attributed to a VERY, VERY old EI conversion kit? I think the IE conversion kit I have in my Prestolite distributor must be at least 20 year old....
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Old 10-14-2017, 08:09 PM
waterlogged882 waterlogged882 is offline
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Quote:
Originally Posted by Tmac in Folsom View Post
OK...it's taken me a while to reply back ... Can anybody help me here?
Yes......
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Old 10-14-2017, 10:38 PM
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thatsmrmastercraft thatsmrmastercraft is offline
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Check the supply voltage and wire connections to the coil. You should have battery voltage with key on/engine off, and while running. If there is much difference, you have a high resistance connection. Might have to do a wiggle test watching the voltmeter. Another place to look is if the distributor is grounded well. This happens through the bolt and clamp that hold the distributor in place. I have seen it happen where too much corrosion on the bolt, clamp, block and distributor caused similar problems.


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Rebuilding Holley Carbs $289
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CUSTOM WHEEL & TIRE PACKAGES

$125 LED LIGHT PACKAGE - FREE SHIPPING
REBUILDING HOLLEY MARINE CARBS - $289 DELIVERED
REBUILT COMPLETE MARINE HOLLEY 4160 CARBS
FOR 302, 351 & 454 STARTING AT $425 DELIVERED
Email - [email protected]
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