My 318 barely starts & runs
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=7278
Printed Date: November-10-2024 at 4:32pm
Topic: My 318 barely starts & runs
Posted By: tleed
Subject: My 318 barely starts & runs
Date Posted: June-29-2007 at 2:56am
When I got my boat back from the rebuilder, it barely started. He thought he had it timed OK, but he used a mark he added at the front, not the factory mark at the back.
So I re-set to 12.5 degrees at 500 rpm from the back. The engine still barely starts. The only way I can get it started is to pour gas down the carb and hold the throttle all the way open. And that's with gas already pooling on the plugs.
I got a Colortune plug, but can't get it to reliably fire. I saw both blue and orange, erraticly before it quit altogether. Oh, and water spurted out of the threads with the Colortune in place.
I put the boat in the lake and it refused to run at speed. Backfired and had poor power at mid-range. Couldn't get rpm above that w/o threat to cut off. I did get it to idle at about 700 rpm, but doesn't seem real smooth to me.
I'm at a loss. I did have it running a month ago. Wasn't a real happy idle, but it did have power. A complete teardown occurred between then and now. The block was bored .030 in the meantime. The carb came back with the idle air bypass turned out between 4-5 times. I turned that back to 1 turn out, but that didn't help starting.
To complicate things, I know my starter is marginal. Too much hard starting. But a "new" rebuilt is 6-13 days away via UPS.
Any thoughts? I'm at a loss where to look intelligently w/o throwing more money at it. I've already been told to change the plugs (they're new).
And as for the poor spinning by the starter, I'm on the hunt for a replacement. Could the relay be part of the poor starter spinning problem? I took it (back) to Advance and they tested it and it refused to spin. So I found a rebuilder who would work on it. He said it was just full of water and rust and pronounced it fine after he cleaned it up and sealed the back plate with silicone. But something's not right...!
Thomas
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Replies:
Posted By: 79nautique
Date Posted: June-29-2007 at 3:12am
sounds like you have a cracked exhaust manifold. and WTF are colortune plugs?
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: tleed
Date Posted: June-29-2007 at 3:58am
"Colortune" is a brand name. Look it up on the web and you'll find all kinds of interesting stuff about it. It's a special plug with a quartz "window" that lets you see into the combustion chamber and watch the color of the flame so you can evaluate fuel mixture. It would be cool if it worked. I saw a few flashes of blue and orange before it quit flashing altogether.
I wondered if I cracked a manifold. Or two. My engine cover got pushed into the front pulleys by a passenger's feet. The belt popped off and overheated badly, which precipitated the rebuild. Wonder if I cracked a manifold at the same time. That would let water back into the cylinders? And make it spurt out of the plug hole, huh?
Thomas
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Posted By: 79nautique
Date Posted: June-29-2007 at 4:32am
ya, and also make it hard to start with water in the cylinders too.
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: BuffaloBFN
Date Posted: June-29-2007 at 11:02am
was this rebuild done by a marine mechanic? did the harmonic balancer get replaced? if memory serves, the counter weight on the balancer is the same on LH vs. RH motors but the timing marks are exactly backwards
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http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold
"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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Posted By: tleed
Date Posted: June-29-2007 at 11:12am
Here we go again:
My engine times from the rear. The timing mark is a pointer on the bellhousing and there's a scale on the flywheel. The balancer was fine and did not get replaced. However, the machinist who did the rebuild put his own mark on the harmonic balancer and one on the front cover. I don't know how he decided where. I re-timed the engine from the back. I wondered if he didn't line up the cam/crank/timing chain properly, but don't know how to check that without pulling the front cover.
But my money is on the cracked manifolds. I have another set going on this afternoon.
Thomas
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Posted By: BuffaloBFN
Date Posted: June-29-2007 at 11:14am
disregard my previous post...if you had water in the motor right after a rebuild?!!?
I'd be knocking on his door
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http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold
"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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Posted By: tleed
Date Posted: June-29-2007 at 11:27am
Well, I am going to compare notes with him today, but cracked manifolds aren't his fault. The theory we developed was that the head gasket blew, but now I'm wondering if there wasn't as much water coming from the manifolds.
Thomas
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Posted By: BuffaloBFN
Date Posted: June-29-2007 at 11:33am
sorry Thomas...my ignorance shows! best of luck with it, I'm sure you're way past dissappointed
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http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold
"It's a Livin' Thing...What a Terrible Thing to Lose" ELO
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Posted By: 79nautique
Date Posted: June-30-2007 at 5:00am
never seen a rebuilt set of exhaust manifolds.
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http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique
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Posted By: tleed
Date Posted: July-01-2007 at 6:13pm
79nautique nailed it.
The cylinders were full of water, which doesn't compress. No wonder my starter was dying.
Apparently my exhaust manifolds warped and/or eroded between the middle 2 cylinders on each side. With the manifolds off, the motor barfed out plenty of water when I cranked it. Most came out of the middle two cylinders, but some came out of the rear, too. The crankcase was already full of milky oil/water. Hence the slight valve tap that came and went.
And the fact that the only way I could get it started was to pour gas down the carb had more to do with displacing the water in the cylinders than any potential problem the carb might have had from sitting over the winter.
Oh, and that liquid on the plug electrodes that smelled a little like gas? It was actually water, with just enough gas to make it smell like gas. No wonder they didn't want to fire.
New manifolds went on yesterday and a fresh crankcase of oil goes in today.
All this in a motor with less than 2 hrs. running time since a complete (bored .030) rebuild.
And, no, the manifolds were not rebuilt. They go on the scrap pile.
Thomas
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Posted By: tleed
Date Posted: July-15-2007 at 3:20am
Just when you think it's safe to go back into the water…
I just installed a brand new set of Barr manifolds and changed the oil. A little water showed up in the oil pan, but I figured that was water getting flushed through the oil system. Dropped the boat in the lake this afternoon. Ran fine about 5 minutes, but it didn't really want to wind up.
Then I took it back to idle and then tried to rev back up. No good. Motor went back to trying to backfire at any revs over about 3000 to 3500. Straight back to the dock. Total running time 10 minutes. Oil on dipstick is all milky and level is way higher.
So I still have water coming in. Question is: where from? I don't know where to look or how to test to find the leak. This motor is a fresh rebuild. Was something installed wrong, or is there a crack in the intake or block we missed? How best to find them?
Thomas
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Posted By: Rinautique76
Date Posted: July-15-2007 at 12:25pm
well the problem i once had with my 76 was i had a machine shop build the motor and the heads were not pressure tested properl;y and there was an internal crack which caused a large amount of water in the crank case in a very short amount of time where the heads machine or did u go with new heads
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ron benoit
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Posted By: tleed
Date Posted: July-15-2007 at 5:34pm
My machinist examined the heads, but I don't think he pressure-tested them. I know he examined them, so I suppose there could have been a crack too small to see. Or an internal one. I think I'm going to compression test today, but that won't uncover a head crack that's leaking to the intake port, but not into the chamber, will it?
I used the same heads. He did shave them to flatten the block surface.
Thomas
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