Ahhhh, hard start and running rough |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Posted: June-01-2017 at 11:37pm |
I bought my 1983 sn2001 last fall. It has the 351 commander.
Sunny Arizona gave us an early start on the season and we've had it out about 10 times. It has ran great, without any real issues. Occasionally, I would have to pump the throttle to get it to fire after sitting in the lake for a bit but that's about it. I had it out on Memorial day for 11 hours. Today, I brought my kids to the lake. The boat fires up and runs great from 10 am til 4:30. While pulling my oldest son on the kneeboard the boat lost power and started to sputter and vibrate. I shut it down immediately. Upon restart the boat will fire but quickly dies. I was able to get it to run eventually and running back to the loading ramp the boat has seriously decreased power, won't pull over 3k rpm and it kind of sounds like a car with a hole in the exhaust. The boat did not overheat. In fact, since I cleaned out the strainer and put a new impeller I've never seen the temp over 110. My plan is to replace the plugs/wires and hope I'm missing on a cylinder or a few. I bought autolite 24s earlier this week but haven't put them in yet. I guess I'm asking if I should be looking at anything else? Thanks in advance. |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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when you pull the plugs, take a good look at the color of the insulators, Rich will be black, Brownish is about right, too lean is white... a hole in the exhaust sound may be a bad exhaust manifold gasket, those can be easily replaced. It sounds like you don't have a functional thermostat, your engine temp should be in the 150-175 range. too cold can cause fouled plugs. I would throw a new thermostat in as well.
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OldSchoolBlue84
Gold Member Joined: December-02-2012 Location: Valparaiso, IN Status: Offline Points: 814 |
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You may want to check your distributor cap for any moisture. I had similar effects and just needed the distributed to dry out. See if anything is spraying within the engine compartment. Good luck
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Kostas
1984 Ski Nautique 2001 |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Well, it looks like bad news. Plugs one, two, six and eight all had moisture on them. Cylinders 1 and 2 shot water all over the place when I turned the motor over. Cylinders 6 and 8 put out a little but not a lot.
I am fairly mechanical and have rebuilt 2 automobile engines and numerous atvs and motorcycles. I am hoping its just a head gasket letting water in. Is there anything else I should be looking for? If the head gasket is blown, i can't really do compression test so what are my options? |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Also, its definitely running rich.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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Sounds to me like a compression test would probably show cylinders 1 and 2 with the same compression or really same lack of compression.
6 and 8 not being adjacent is more puzzling but a compression test on all 8 seems like a good starting point. The noise was probably exhaust noises in the carburetor if there's a leak between 1 and 2 letting exhaust from one cylinder go into the other while it's intake valve was open |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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I'll do a compression test tomorrow morning and post the numbers. To me, water in the cylinder means blown head gasket or cracked block. After doing the compression test, I'm going to pull the heads unless someone says otherwise.
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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I would say it's less than 5% chance this is head gasket related. Any recent overheats? After compression test, start disassembly but don't pull the heads right off the bat. Exhaust or intake manifolds should be much higher on the suspect list. I suggest reporting back here with compression test results before moving on. Be sure to drain the water from the engine before anything, and get the water out of the cylinders before the test.
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Gary S
Grand Poobah Joined: November-30-2006 Location: Illinois Status: Offline Points: 14096 |
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+1 what Tim says. He walked me thru the manifold thing on the Shamrock. Pulled the manifold on the side that water was in - you could actually see the rust track the water left in the manifolds exhaust port
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Ok, you guys are awesome. I love the support on this forum. The numbers are as follows:
1 - 30 psi 2 - 30 psi 3 - 125 psi 4 - 140 psi 5 - 120 psi 6 - 120 psi 7 - 120 psi 8 - 120 psi I guess I will pull the in take and then exhaust and go from there. Thanks for the help so far. |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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I bought the boat last fall (october) The first time I took it out it was overheating, It never got hotter than 190. I cleaned the strainer and it has ran 110 ever since. It possible, maybe even likely that the previous owner overheated the boat. I have had it out 8 times without issue (until yesterday) since I cleaned the strainer.
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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As the pictures show, water is getting in by cylinders 1 and 2. The other bank doesn't show much on the intake side. The intake gaskets look pretty decent. Should I peel them off and see what the head surfaces look like? Also, the oil in the pan doesn't show evidence of water. I'm sure if it had run much longer, that would have changed. |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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you're going to need new intake gaskets when you re-assemble. pull those gaskets off and clean everything up. leaking intake manifold doesn't explain your loss of compression though, that is a function of the valves/rings. Do you have a leak down tester by any chance? If not, they can be had at harbor freight pretty cheaply. A leak down tester will show the source of the problem, and what your next step is.
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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With 30 pounds in both #1 and #2 and water in both you've got some issues that involve a new head gasket or two one way or another
They're connected together in ways they're not meant to be thru either a cracked or warped head a cracked or warped block or if you're really lucky a bad head gasket. That sure looks like a crack though in the water jacket at the back of the #1cylinder and you might find the other end of that crack in the top of the block. |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Thanks for the input so far. I'm having a hard time figuring out how this issue could suddenly manifest after 50 hrs of great use without overheating or anything. When it started to run rough, the temp was 110, I could put my hand on the block, exhaust... I'm going to check on suspected crack area. I've pulled the exhaust and banks 1-4 had water in them, but that was expected with all the water in 1 and 2. The other side was dry.
What should I be looking for on the exhaust manifolds for failure or a water issue there? Should I pull the heads or wait for some more input? |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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I know what I'd do, but I like tearing things apart.
Why don't you wait for some input from those who think it's something else like manifolds. To me the big factor is EQUAL and low compression in those two adjacent cylinders. Nothing you can do with an intake or exhaust manifold is gonna get you back to normal compression on those two cylinders Meanwhile see if that's a crack in the back of #1 cylinder. My guess is that the guy you bought it from might have an idea about how it could happen. |
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TRBenj
Grand Poobah Joined: June-29-2005 Location: NWCT Status: Offline Points: 21171 |
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Kens right, not (just) an intake or exh manifold issue with those compression results. I'd still be looking for intake or exhaust manifold damage as you disassemble... but that head has to come off at a minimum. Same goes for the exh manifold on the other side (sounds like both banks had water in the cylinders).
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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There doesn't appear to be a crack. At least nothing I could easily identify. Here's a pic after wiping down some of that water infested oil.
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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I'm hoping this means I beat the odds and fall into the 5%. It definitely looks like the head gasket between 1 and 2 is gone. What do you guys thing?
Replace the gaskets, reassemble and hope for the best? Try to locate some gt40p heads and replace the heads while I've got everything disassembled? Any other options or considerations I need to look into? |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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yes, that head gasket is bad... put a straight edge on the block and check for warpage... machine the head (minimum) and have the valves checked or put on rebuilt p heads as you suggested earlier. I honestly think the rebuilt heads are going to serve you better in the long run, and are not much of a premium over having yours fixed. Head gaskets get blow from getting hot, and having the heads or block warped. it can take a bit for them to show themselves, so while 50 hrs is a long time between overheat and gasket failure, I would be looking for warped parts and getting it all flat before you re-assemble. I wish that you had gotten a feeling for the rings before you pulled the head off, Your other cyl compression numbers looked good, so I am hoping that speaks to the condition of the rings in 1 and 2.
Don't slouch on testing manifolds, they can quickly mess up all the work you are going to be doing to get the top end fixed. |
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Dreaming
Platinum Member Joined: May-21-2010 Location: Tacoma, WA Status: Offline Points: 1870 |
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Look at the yard sale post in the for sale section... Jody may be able to hook you up on the top end pieces... I saw a head, and intake/carb etc... might be your lucky day
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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I see basically a superhighway between the 2 cylinders to explain the equal compression readings and then there is an "entrance ramp" into that highway from the water passage that would explain the water in both cylinders. I think it's your lucky day but you should put a straightedge on the head and the block to check for straightness Since the manifolds are off, I'd at least run water thru the water side and see if any shows up on the exhaust side. People have all kinds of ways of checking varying from just flowing water to pressurizing the water side and checking the pressure drop. You can search on CCF about testing them. You still had some amount of water in 2 cylinders on the other side that could be from head gasket issues or maybe an exhaust manifold issue. Don't know how many hours or the condition of the heads so replacing with GT-40P's would be up to you then you might start thinking about intake manifolds and cams and adding up the dollars. Oh and one last thing...................go out and buy a lottery ticket or 2 or 3 cause like I said, I think you got lucky Good luck especially with the lottery tickets |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 11061 |
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Besides the reasons mentioned for head gaskets leaking, they can just plain get old and wear out too, so who knows what happened before you bought the boat.
It may have just been the end of the road for the original gaskets. By the way, I'm gonna get a few lottery tickets for myself PS A leakdown test in this case would have told you nothing |
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desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
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I doubt you bent any connecting rods but you may want to turn it over by hand and make sure all the pistons come up to the top of the cylinders. Better to find out now rather than later.
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desertskier
Platinum Member Joined: December-19-2006 Location: Az Status: Offline Points: 1115 |
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joshjanae
Groupie Joined: October-11-2015 Location: Arizona Status: Offline Points: 87 |
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Well, I have good news and bad...ish. The good is that the block isn't warped and I can't locate a crack visually. The bad...ish. The head on the the side where the gasket was blown is out by about .006. Guess that explains why it failed. I say bad...ish because when I talked to the wife about getting new heads she wasn't too excited. Now, I don't have to feel too bad about buying them . So next step, new heads.
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