Near disaster from carb

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Thomas Sottile
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read the owners manual

#16 Post by Thomas Sottile »

If you don not have a owners manual get one, then read it most of the miner questions can be answered.

Dick Weiss
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Re: Near disaster from carb

#17 Post by Dick Weiss »

Mitch,

You already have 3-fuel filters in the system--you don't need another in-line filter if the fuel tank's been cleaned out and sealed.
I've been removing the "cheapy" VW plactic filter(s) for years as they'er smaller--including their nipples being smaller & needing hose clamps; Thusly, I don't add extra filters when rebuilding or servicing 356s & 912s. Also, I use the OEM braided 7mm fuel hose and NO clamps.
My 4-cam has the common 2-filters in the petcock, 1-in the pressure regulator, 1-each in the carb inlet banjos for a total of 5.

As mentioned by others, stuck needles, excessive fuel pump pressure, &/or a sunken float--especially 1-or both in Solexs, or
1-of 4-floats in Zeniths, and not forgetting the Webers w/their adjustment setting.

Dick

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David Jones
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Re: Near disaster from carb

#18 Post by David Jones »

Rotating the engine backwards means the valves will open before you reach a compression stroke thereby blowing excess fuel out of the exhaust port. By doing this you may be able to avoid taking out the plugs. A little gas in the oil will not harm the engine too much. After all 2 stroke lawnmower engines run on a 50 to 1 mix of oil and gas and the bearings last on them. I know they are designed for that oil/gas mix but as long as you have oil pressure you are likely OK. Keep in mind that ships have used water lubrication many times for propeller shafts. It is not about the lubricant it is about preventing metal to metal contact.
By the way Mitch you still need to fix your profile and add the Email icon
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Doug McDonnell
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Re: Near disaster from carb

#19 Post by Doug McDonnell »

Counter clockwise is off position for the fuel handle. Backwards as Wes mentioned means with a wrench on the pulley nut turn the nut counter clockwise when standing behind the engine.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Mitch Covington
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Re: Near disaster from carb

#20 Post by Mitch Covington »

Dodged a bullet, I think.

Today I drained the oil, which poured out like water it was so thin from being cut by the gas. I got just under 5.5 quarts out, including the filter container.

The oil in the filter container was still thick and seemed uncut by gas. This would imply that the engine did not run much, or at all, during the gas intrusion, right? Most gas leaked after shutdown for the night.

There was essentially nothing on the sump plate magnet.

Looks promising. Thanks for all the help!
Mitch Covington
Asheville, NC
'59 356 Cabriolet
'79 911 SC Targa

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Doug McDonnell
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Re: Near disaster from carb

#21 Post by Doug McDonnell »

While you may be able to clean the valve you can buy new. Just take sure they are Solex and marked 175. I soaked mine in Yamalube carb cleaner overnight and blew it out with compressed air and it worked fine then. If you opt for new ones do not throw the old one away. Keep it for a spare after cleaning.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Doug McDonnell
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Re: Near disaster from carb

#22 Post by Doug McDonnell »

Mitch Covington wrote:Dodged a bullet, I think.

Today I drained the oil, which poured out like water it was so thin from being cut by the gas. I got just under 5.5 quarts out, including the filter container.

The oil in the filter container was still thick and seemed uncut by gas. This would imply that the engine did not run much, or at all, during the gas intrusion, right? Most gas leaked after shutdown for the night.

There was essentially nothing on the sump plate magnet.

Looks promising. Thanks for all the help!
No it only means that the engine never got warm enough to close the bypass valve. But if the Porsche Gods look down on you kindly the contamination was mostly after you shut down and with new oil and good valve all will be OK.
1965 356C 2000 BMW 740i Sport 1967 Honda CL77 There is never enough time to do it right, but always enough time to do it over.

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Mitch Covington
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Re: Near disaster from carb

#23 Post by Mitch Covington »

Dick Weiss wrote:Mitch,

You already have 3-fuel filters in the system--you don't need another in-line filter if the fuel tank's been cleaned out and sealed. Dick
That's good to know! I certainly don't want to fix what ain't broken. There've been threads about this topic, and it seems like many have added them... whether in the engine compartment or under the car; glass vs plastic vs metal, etc.
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Re: Near disaster from carb

#24 Post by Mitch Covington »

David Jones wrote:Rotating the engine backwards means the valves will open before you reach a compression stroke thereby blowing excess fuel out of the exhaust port. By doing this you may be able to avoid taking out the plugs.
Exactly the kind of answer I was looking for, thanks!
David Jones wrote:A little gas in the oil will not harm the engine too much. After all 2 stroke lawnmower engines run on a 50 to 1 mix of oil and gas and the bearings last on them. I know they are designed for that oil/gas mix but as long as you have oil pressure you are likely OK. Keep in mind that ships have used water lubrication many times for propeller shafts. It is not about the lubricant it is about preventing metal to metal contact.
Makes sense.

David Jones wrote:By the way Mitch you still need to fix your profile and add the Email icon
Done. Thanks for pointing that out, didn't realize that I had email turned off.
Mitch Covington
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Re: Near disaster from carb

#25 Post by Mitch Covington »

Doug McDonnell wrote:Counter clockwise is off position for the fuel handle. Backwards as Wes mentioned means with a wrench on the pulley nut turn the nut counter clockwise when standing behind the engine.
I know HOW to turn the engine backwards, just wondered WHY it makes a difference when in this situation. David Jones answered that superbly. I love picking up these tidbits here... these are things that you might not get in the manual.
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Mitch Covington
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Re: Near disaster from carb

#26 Post by Mitch Covington »

Doug McDonnell wrote:While you may be able to clean the valve you can buy new. Just take sure they are Solex and marked 175. I soaked mine in Yamalube carb cleaner overnight and blew it out with compressed air and it worked fine then. If you opt for new ones do not throw the old one away. Keep it for a spare after cleaning.
Thanks, good advice. I rarely throw away any part from these cars, even if I know it's bad. Properly labeled, it's good to keep so that you know what was in there before. Usually I find that the part wasn't bad or the culprit to the problem, so of course it makes a great spare.
Mitch Covington
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'79 911 SC Targa

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Mitch Covington
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Re: Near disaster from carb

#27 Post by Mitch Covington »

Doug McDonnell wrote: No it only means that the engine never got warm enough to close the bypass valve. But if the Porsche Gods look down on you kindly the contamination was mostly after you shut down and with new oil and good valve all will be OK.
Yes, the engine got plenty hot. I had just driven it more than 4 miles of moderately aggressive driving, after warming it up.

Could you elaborate on what you mean about the bypass valve? I assume you mean the oil system bypass valve, but are you implying that there could be something wrong with mine?

thanks Doug.
Mitch Covington
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Vic Skirmants
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Re: Near disaster from carb

#28 Post by Vic Skirmants »

"No it only means that the engine never got warm enough to close the bypass valve."
If you are referring to the vertical plunger in the timing cover, it closes as soon as oil pressure is present in the main galley. Heat has nothing to do with it.

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Re: Near disaster from carb

#29 Post by Ron LaDow »

Vic Skirmants wrote:"No it only means that the engine never got warm enough to close the bypass valve."
If you are referring to the vertical plunger in the timing cover, it closes as soon as oil pressure is present in the main galley. Heat has nothing to do with it.
+1, assuming you're referring to the circuit controlled by the valve Vic mentions.
This is a 'priority-mains' valve that feeds initial pressure to the main bearings. *After* they get pressurized, a circuit back-loads this valve and redirects the flow to fill the cooler.
Outside of the ill-fated '57 thermo valve, there are no thermostatic provisions in the lube systems of any 616 engine.
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Mitch Covington
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Re: Near disaster from carb

#30 Post by Mitch Covington »

I have the bad carb off the car. I was leaning toward sending it out for rebuild, but since that will take a month or two to get the pair back, I want to at least disassemble what I safely can myself. I want to see the float and the needle valve myself. Before i do... a couple of questions.

I thought the top cover would come right off, but it seems glued down pretty tight. Should i just pull harder, or pry it off somehow. The last thing i want to do is damage the carb. Are there any tricks for this?

Should i get a basic gasket kit and replace what i comfortably can, like at least the needle valve and easily accessible gaskets?

thanks!
Mitch
Mitch Covington
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