57 Fastwin - Down a cylinder

vote4me4pres · Jul 24, 2009

I was having trouble with getting full power out of this motor so I replaced the coils and rebuilt the carb. Was running great Monday and Tuesday, but I took it out yesterday and the bottom cylinder would not fire. Still getting spark so I think its a fuel issue, but it doesn't make sense that one cylinder has a problem and not the other. Any thoughts?

ryendube · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

vote4me4pres said:
I was having trouble with getting full power out of this motor so I replaced the coils and rebuilt the carb. Was running great Monday and Tuesday, but I took it out yesterday and the bottom cylinder would not fire. Still getting spark so I think its a fuel issue, but it doesn't make sense that one cylinder has a problem and not the other. Any thoughts?

your definetly gettin spark? how you know its not firing ? Plug wet? (well more so than an old 2 makes it?)

vote4me4pres · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Spark jumps a 1/4inch gap. Plug is black and oily. I can hear, feel, and hearing it missing. Will go about 5mph when it was doing 16mph.

ryendube · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

vote4me4pres said:
Spark jumps a 1/4inch gap. Plug is black and oily. I can hear, feel, and hearing it missing. Will go about 5mph when it was doing 16mph.

Ummm not an expert on outboards but the holy trinity is fuel, ignition and compression. You have those you have a runnin motor. Check the compression.

tmcalavy · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Check for spark on both jugs. Sometimes a coil will drop out under load after it heats up...retrace your steps on replacing the coil. Sounds like one coil/cylinder is dropping out under load...could be something as simple as a loose connection or short in the plug wire. A spark tester from Harbor Freight will allow you to check spark while its running.

Sea18Horse · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Compression test? I presume you've swapped spark plugs? How big a gap will it actually jump? Same as the good one? Are you still running a pressure tank or converted to fuel pump? If fuel pump, diaphram could be leaking. Take the air silencer off and see if it spits out the carb. Reed valve could be broken or have a piece of crud in it. Pretty rare but I understand it's posible. Good luck!

Cheers...............Todd

ryendube · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Sea18Horse said:
Compression test? I presume you've swapped spark plugs? How big a gap will it actually jump? Same as the good one? Are you still running a pressure tank or converted to fuel pump? If fuel pump, diaphram could be leaking. Take the air silencer off and see if it spits out the carb. Reed valve could be broken or have a piece of crud in it. Pretty rare but I understand it's posible. Good luck!

Cheers...............Todd

He said it jumps a 1/4inch. fuel wouldnt only affect 1 cylinder. and it is getting fuel. thought he already swappped the plugs.

ryendube · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

tmcalavy said:
Check for spark on both jugs. Sometimes a coil will drop out under load after it heats up...retrace your steps on replacing the coil. Sounds like one coil/cylinder is dropping out under load...could be something as simple as a loose connection or short in the plug wire. A spark tester from Harbor Freight will allow you to check spark while its running.

I like his answer, thought you went through testing spark. I know one of mine acted like it was missing (stumble under load) and it was a dead cylinder, rings stickin. Ran all nice and smooth without load.

Sea18Horse · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Quote:
Originally Posted by Sea18Horse
Compression test? I presume you've swapped spark plugs? How big a gap will it actually jump? Same as the good one? Are you still running a pressure tank or converted to fuel pump? If fuel pump, diaphram could be leaking. Take the air silencer off and see if it spits out the carb. Reed valve could be broken or have a piece of crud in it. Pretty rare but I understand it's posible. Good luck!

Cheers...............Todd

He said it jumps a 1/4inch. fuel wouldnt only affect 1 cylinder. and it is getting fuel. thought he already swappped the plugs.

Quote:
Originally Posted by tmcalavy
Check for spark on both jugs. Sometimes a coil will drop out under load after it heats up...retrace your steps on replacing the coil. Sounds like one coil/cylinder is dropping out under load...could be something as simple as a loose connection or short in the plug wire. A spark tester from Harbor Freight will allow you to check spark while its running.

I like his answer, thought you went through testing spark. I know one of mine acted like it was missing (stumble under load) and it was a dead cylinder, rings stickin. Ran all nice and smooth without load.

Critiquing our responses now? Excellent! I'm sure tm is feeling all warm & fuzzy right now seeing you approve of his suggestion. I know I would be. Tell you what, next time I want to suggest something I'll run it by you first. How would that be?

Cheers.................Todd

Chinewalker · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Any evidence of water beading on the oily plug? That might point towards a blown head gasket... Should show up if you do the compression test suggested above...

samo_ott · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Do a compression test and pull 1 plug wire off at a time when it's idling. If one wire does nothing to the rpm's that's the dead cylinder...

ryendube · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Sea18Horse said:
Critiquing our responses now? Excellent! I'm sure tm is feeling all warm & fuzzy right now seeing you approve of his suggestion. I know I would be. Tell you what, next time I want to suggest something I'll run it by you first. How would that be?

Cheers.................Todd

I apologize if it came off like that I was merely stating why I said do a compression test which you obviously questioned.....and also pointing out what he had already stated in his post .
As for I like his answer comment it was a thats a good point he knows what hes saying.
Did not mean it the way you took it but feel free to jump down my throat anytime.

Sea18Horse · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Hehe, actually my post was meant for the o/p. Compression test? = Have you done a compression test yet? Since it took me a while to make my post I hadn't seen your recommendation for a compression test.

He said it would jump 1/4 inch. But will it jump 5/16"?, 3/8? 1/2 inch? How about the good cylinder? If the bad cylinder will jump 1/4 inch and no more, but the good cylinder will jump 5/8", does that not seem like a useful clue?

Yes I agree, a carburation problem could not effect only one cylinder. But a fuel pump diaphram leaking into the bad cylinder could.

Yes he may well have swapped plugs. But he didn't say he did. I never assume anything.

Misunderstanding, lets move on.

Cheers.......................Todd

vote4me4pres · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Did a comp test this afternoon. 87 on top, 88 on the bottom. Changed plugs while I was out there twice. A set of champions, autolites, and nkg - all equivalent. 1st change help initially, but not fixed and only temporary. An in-line checker while I was flushing it out showed both working. I replaced the plug wires and fuel lines today, will see what happens tomorrow.

vote4me4pres · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Still running the pressure tank.

samo_ott · Jul 24, 2009

Re: 57 Fastwin - Down a cylinder

Did you pull the wires off the running engine one by one? what happened?

ryendube · Jul 27, 2009

Re: 57 Fastwin - Down a cylinder

vote4me4pres said:
I was having trouble with getting full power out of this motor so I replaced the coils and rebuilt the carb. Was running great Monday and Tuesday, but I took it out yesterday and the bottom cylinder would not fire. Still getting spark so I think its a fuel issue, but it doesn't make sense that one cylinder has a problem and not the other. Any thoughts?

sorry one thing I missed and forgot to ask is this the same problem prior to swapping parts? the trouble of full power? what made you deside to swap coils etc.

just reading your on water plug change helping for a bit then nothing. so is the lower cylinder firing now and your just not getting good power ? or what.

if you just posted the above on water change I would say your running way rich and fouling your plugs.

57 Fastwin - Down a cylinder

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