#1
IP: 71.241.216.122
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Sudden loss of power
This is my first posting on the A4 forum so bear with me if I make some obvious mistakes.
I just put my Triton in the water to make the 2 hour journey from the yard to my mooring. For one and three quarter hours everything was going swimmingly. I was making over six knots and the engine was purring. Just rebuilt the carb, changed the plugs, new raw water impeller, new plugs, new thermostat and bypass, new oil. Then suddenly everything went south. Sudden loss of power, but not complete loss. Engine clearly not firing right. Excessive vibration. I was able to limp home to the mooring with the speed getting slower and slower. By the time I arrived I was barely making 2 knots. I sounded like one of those old popping diesel engines At first I thought something may have snagged the prop but symptoms continue when shifted to neutral. My gut tells me this is distributor or timing related, but with my limited mechanical know how I'm not sure if that's worth much. What I can tell you is that it seemed to be a singular event - working perfectly one second then clearly something was wrong. The oil pressure stayed good the whole time. Water flowed from the exhaust with no problem. The temperature gauge definitely went way down. I guess I'll start by replacing the distributor or at least parts of it. If this seems symptomatic of something else or if I have left out some valuable information please weigh in. Thanks. |
#2
IP: 24.89.230.235
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Hi,
Well, it could be many things. But I will just list off some OK. You will have to check each one. Typically, if the timing bolt was tight it's probably not timing...so we probably don't have to look right there first. -check all plug wires and ensure one or two didn't chafe on the alternator or something. -ensure all wires are on securely -coil malfunction can cause loss of power and ignition. Allot of times the coil issue results in complete loss of power....other times it just misses and looses power. Should you start the engine when it cools down and it runs fine the coil should be the main suspect at that time. -sometimes a valve or valve spring can be damaged. This typically doesn't happen underway and under load, but it is something to keep in the back of your mind. -remove plugs and look and see if there is water on them. Gas looks wet...water leaves a bubble. If your manifold developed a rust hole or something it could be spraying water into the combustion chamber and putting out the fire...again, could happen. -water in fuel will cause loss of power and sputtering. -something on the prop can slow the boat and ***with all that said, is sure sounds like an ignition problem. Allot of people get fixated on prop and vibration. The reverberation of a poorly firing engine can radiate sound to the drive train and it can feel like the shaft is coming out of the boat...knocking and banging.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#3
IP: 71.118.13.238
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Question & quick check
AIM, did you try the choke? And if so what happened?
When an engine looses power or begins to stutter a good check is to engage the choke and see if it helps while engaging slowly. Dave Neptune |
#4
IP: 24.152.131.153
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My first instinct was fuel all the way but that was a knee jerk reaction.
Rough running and popping all of a sudden makes me wonder if the distributor was fastened tight. If not, the rotation of the dist shaft would try to twist the dist body clockwise resulting in severely retarded timing. As it continued to move the symptom would worsen. Grab the distributor and see if it rotates by hand.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#5
IP: 99.124.190.130
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Like Neil, my first reaction was FUEL. Clogged main jet, sediment in tank disturbed by the passage, etc. But you know your fuel system better than I do (tank clean?, primary and secondary filters?, etc) so I could be wrong. But try pulling out the choke and see if it runs better. If so, clean the main jet.
Ignition? Perhaps the distributor shifted a bit? Broken advance spring? Probably not a bad coil - a bad coil and the engine dies like it was shot! ..until it cools off. |
#6
IP: 24.108.64.169
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Try replacing the condenser. The one in there now might be defective even if is newish. Sounds just like what I went through a few years ago the only time in 27 years the A4 let me down.
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#7
IP: 72.95.89.115
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Thanks for all the replies.
I will be returning to the boat in a few days and will get back to you. Is replacing the condenser a straightforward proceedure? Just about everything I do now will be for the first time thanks again AIM |
#8
IP: 24.108.64.169
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Changing the condenser is easy if you can see what you have to do. Just be careful not to drop the little bolt that holds it in place.
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#9
IP: 74.101.155.102
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I agree with your gut, that you should look carefully at your distributor cap and rotor. Label the plug wires and where they go onto the cap very carefully before taking them off!! Replacing both is cheap and easy.
The cap might have cracked or worked its way loose, resulting in misalignment with the rotor and inconsistent firing. The cap contacts underneath might be carboned up or worn - wipe with a bit of acetone or replace it The rotor might be broken or worn. The rotor spins around pretty fast as the engine runs - it's been interesting to me to see how hosed up it and the cap can be even though the engine runs pretty well. I do agree with the suggestion that you convert to electronic ignition, as it helps rule out condenser and points issues that are possible but not likely causes here - but I would NOT do that until this has been solved. This is going to be caused by one minor thing out of a lot of potential minor things, and there is no need to introduce more variables into the equation. |
#10
IP: 71.181.37.27
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As mentioned by others , I would bleed the carb thru the main passage plug. A common
issue when gas has been stored over the winter. I would also check that all the plugs are firing by removing wires one by one and looking for difference in rpm. Remove plugs and look for fouling as well. |
#11
IP: 72.95.89.115
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Once again thanks for the replies.
You have no idea welcome these tips are. I was thinking about it overnight and I think the fuel idea could be right. I will also plan on replacing the distributor cap and condenser as a precaution. So I can flush the carb without having to remove it? i'm dreading removing it while the boat is in the water. Well to be more accurate I'm dreading having to put it back on while the boat is in the water. I barely have enough room to get my hand in between the carb and the bulkhead. Reattaching the choke cable and its housing was a royal PITA. I ended up changing the screws and nuts to match the tools i could fit into the gap. I replaced the gas filter a couple of weeks ago. i poured the contents into a clear container and i thought it looked ok (yellower than I expected but no visible particulates). I put some stabilizer in the gas at the end of last season Do you think I need to drain and flush the whole tank? I'm not sure where I would put all of that gas. |
#12
IP: 71.181.37.27
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You should have a new one of the Fuel water separators that MMI supplies and
also a in line filter before the Carb to keep particles out of carb over season and during storage. Don Moyer's Carb flushing procedure involves removing the main passage plug ( be sure to place rags underneath so don't lose plug in bilge first. He recommends flushing a cup or so through the passage hole . Gather the gas in a container and make sure bilge is completely dry and free of gas fumes before starting. |
#13
IP: 24.152.131.153
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Quote:
Have you considered cutting a generous access hole on that side of the engine? You'll be removing the carburetor as a regular maintenance routine so you may as well make it as easy as possible. You can always close up the hole with a removable panel or door.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#14
IP: 206.125.176.5
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I hand pumped my mostly full 18 gallon fuel tank last year after it was contaminated with water..I used the $8 multi-use plastic pump from the auto boutique..it was not the quickest, but getting the fill hose off, and getting everything set up took just as long..I duct taped a piece of stiff plastic to the hand pump pick-up hose to keep it from rolling around in the tank, and to get it to the bottom of the tank. The adhesive in the duct tape lasted just long enough to get the fuel out.
I don't even think I finished a beer when the pumping was done. I pumped mine into 3 jerry cans, took it home, got the water out of it about a gallon at a time in a big pitcher (letting the water sink to the bottom and pull the fuel off the top), and I burn it in the lawnmower. I think the yellow comes from the corn in the fuel. Non-ethanol fuel is NOT yellow, even months later. Good luck with determining carb access..as mentioned, it really is a regular maintenance item and much easier to work on out of the engine compartment.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#15
IP: 161.213.49.150
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Quote:
TRUE GRIT Edit: AIM - Just read your post #16. Put a crumpled rag under the work area. It will catch the parts you are going to drop. Last edited by JOHN COOKSON; 06-04-2014 at 12:56 PM. |
#16
IP: 72.95.89.115
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"I don't understand what difference it makes whether the boat is in the water, on the hard or on the moon. It's location doesn't affect carburetor access."
I guess my reasoning is that it seemed like a challenge to get everything attached without dropping half of it in the bilge, and this was on a level, non-moving boat. Out on the mooring I can't see it getting any easier. i will look into expanding the free space around the carb area. SAS - when you pumped out your tank did you clean it out in any way or did you simply fill it with new gas? "He recommends flushing a cup or so through the passage hole " Can you point me to a link for this. Do I just let the fuel pump pump a cup of gas through and collect it? |
#17
IP: 71.241.216.107
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Update:
Well i made it back down to the boat yesterday and it didn't take very long to find the or a problem.
I have a significant amount of water in the oil. Thick, white and 2 to three inches higher on the dipstick than the fill level. I'm not really sure where I go from here. Is it possible for water to get into the engine from the spark plug wells. When I first replaced the thermostat i had a significant leak around the housing after reattaching. water pooled up in all four of the spark plug wells. I took the housing off and reattached it, this time with plenty of permatec red and I thought I had fixed it. However when I looked at the engine at the end of that first trip I saw a small amount of water pooled in well #1. I'm not sure if this had come out from the inside or pooled from the outside. Should I try to get the engine running to heat up the oil or try to drain as much as I can get out cold? On a thermostat related note. Can someone refer me to a diagram showing the flow of cooling water through the engine. I still don't have a feel for what the thermostat (and my newly installed MMI bypass loop) are doing. If I have a bypass loop with a cutoff valve doesn't this make a thermostat redundant? Thanks Andrew |
#18
IP: 199.36.244.16
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Quote:
Did you possibly have a no start or tough-to-start issue where you were cranking the engine with the raw water intake valve open? If so, that could explain where the water came from. After you reply we can explain and educate you better on this... You'll need to get the oil changed out immediately. Do at least 3 oil changes until you see no more signs of water in the oil. One other concern I have is the possibility of a head gasket. Could explain your sudden loss of power in your earlier post. I'll let others weigh in on that... Can you do a compression check for us? As requested, attached is a cooling flow diagram. In the future, you can find a library of this stuff in the "Drawings and Schematics" section. http://www.moyermarine.com//forums/f...c&daysprune=-1
__________________
-Jerry 'Lone Ranger' 1978 RANGER 30 |
#19
IP: 64.222.228.25
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Thanks road.
I didn't really have any problem getting the engine running (in the yard to get the oil warmed up or on water to make the trip to the mooring.) I'm assuming I change the oil without trying to get the engine running as this might just introduce more water into the system?? I have never performed a pressure test so I will need to look at some previous posts to figure out what to do. A |
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