#1
IP: 50.92.238.107
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No compression
Hey Guys,
Met a young couple on the dock today who just bought their first boat. There is a great looking A4 that won't start. They were told it hadn't run in a few years. turns over fine. Their local mechanic told them there is no compression and that he needs to take the engine out. Shouldn't they try loosening the valves first? Take off the valve cover, spray some penetration oil, persuade the valves to loosen up? I haven't had to go that direction as of yet, but picked up that idea from endless lurking here. Thanks!
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Marty 1967 Tartan 27 Bowen Island, BC |
#2
IP: 172.222.238.142
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Marty, absolutely suggest they give resurrection a try. My engine had been frozen for a few years when I bout her and once I got her to spin she ran well for 35 years for me and is still getting the new owner around. Well worth the effort!!!
Get them on the forum if you can. Dave Neptune |
#3
IP: 98.171.161.182
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Quote:
Low compression across the board that improves when oil is added to the cylinders? No compression in two adjacent cylinders? No compression in two non adjacent cylinders? The first thing I'd do is repeat the compression test myself. TRUE GRIT |
#4
IP: 50.92.238.107
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compression
For my own knowledge base:
"Low compression across the board that improves when oil is added to the cylinders" = mediocre rings? "No compression in two adjacent cylinders" = likely head gasket or head issue? "No compression at all" = stuck valves???? Thanks! Marty
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Marty 1967 Tartan 27 Bowen Island, BC |
#5
IP: 98.171.161.182
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Quote:
If there is no compression in just one cylinder the cause is most likely a stuck valve. Did the mechanic explain why the engine needed to be pulled and the compression problem could not be fixed in situ? TRUE GRIT |
#6
IP: 73.129.213.235
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I have had a lifter stick and cause no compression too.
James |
#7
IP: 98.171.161.182
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Marty
Echoing what Dave N. said; have these folks join the forum so we can deal with this on a one on one basis. Few mechanics are honest and competent. Most aren't worth a pitcher of warm spit when it comes to A4s. Afourians excepted, naturally. TRUE GRIT |
#8
IP: 76.179.119.203
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Quote:
As others have said, get them online, and maybe loan them your MMI manual for a few days....
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Jeff S/V Bunny Planet 1971 Bristol 29 #169 |
#9
IP: 50.92.238.107
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compression
Thanks for the replies.
Yes, they have the manual and tools, and I have strongly urged them to join the forum. I am hopefully meeting them later today, so wanted to be sure my advice was sound. Loaning them penetrating oil and gaskets. The mechanic was also the p.o.'s mechanic, and has been responsible for the A4 for a while. His work looks very good. New owners told me he plans to pull the engine and fix and reinstall within two weeks. I am also encouraging them to see this as a learning opportunity as they plan to cruise extensively and have little experience. They seem eager to learn and ask lots of questions. Showed them what to do to remove the carb, and then the valve cover, and they plan to do that. I have to say the access is terrible on that part of the engine (C & C 33). Engine was running last fall, and it is fresh water cooled, so seems unlikely the gasket failed over the winter....? Time permitting I will run my own compression test, as they seem a little vague on the details. Well, hopefully they will pick up the thread soon.
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Marty 1967 Tartan 27 Bowen Island, BC |
#10
IP: 73.28.211.141
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Some red flags.
Take out and fix within two weeks? Sounds like he knows exactly what is wrong and just wants to make it look good and get more money. Doubtful! He needs to remove head and see what is going on, so he can give an estimate of what it may cost and what is needed to get it going. Rebuild? Valve job? just stuck valves? Big difference in cost and time. Just knowing an engine has no compression a mechanic cant give an estimate of the repair. More diagnoses needed to be done. |
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#11
IP: 50.92.238.107
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have compression - no spark
Atomic Brainiacs,
Looks like the mechanic was pretty far off. I was on my friends' boat today and took them through some initial troubleshooting. Found there was no spark cranking and holding the plug to the block. Opened the distributor (was converted to EI) and found the rotor looked shot - worst I've ever seen. Had a spare rotor to try, but still no spark. While the plug was out cranked and felt my thumb pushed off by compression. My question at the moment is: Noticed the coil was quite warm at the top although cranking was maybe two x 30 seconds. Is that indicative of a coil problem? I had to take off but left a spare coil and distributor cap for them to swap out. I suspect tomorrow we'll be exploring the gas supply once we have spark - didn't smell any fuel after cranking. I think the mechanic changed the racor filter, so maybe it was still empty and needs more cranking to fill. I know you are supposed to pre-fill, but assuming nothing. The other issue is that the batteries sound low: cranking but not as fast as it should. Queston two: Can a low battery still create a good spark?
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Marty 1967 Tartan 27 Bowen Island, BC |
#12
IP: 32.211.28.40
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Marty,
Sounds like these folks should be hiring you as their mechanic... I don't have EI, but a hot coil after 60 sec of cranking doesn't sound good. How long was the key in the ON position (assuming current to the coil the whole time)? Sounds like you're back to the basics - compression, spark, fuel. And it sounds like you may have issues with all three. Personally, I'd address the compression first - likely to be the long pole in the tent! |
#13
IP: 50.92.238.107
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tracking it down
Having fun helping out ...plus the boat karma thing.
I left my compression gauge with them, and they figured out how to use it. Quick learners. They just called to report that all cylinders have 85-100psi! So, compression is good. Thanks for the thought about the ignition left on - that might explain the heat. New owner also reports plugs were wet w/gas - so that's looking good. They also migrated their ignition wires to the spare dist cap I left there, and report now yellow spark at three cylinders, and a whiter spark at one. Wish I had thought to bring my meter! So can bad coil and/or low battery = poor spark? Thanks!
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Marty 1967 Tartan 27 Bowen Island, BC |
#14
IP: 50.92.238.107
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spark
....poor negative ground?
....failing ignition wires? ....or....?
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Marty 1967 Tartan 27 Bowen Island, BC |
#15
IP: 98.171.161.182
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Do a check of the distributor towers to see if there is any corrosion in them that is making the weak spark. The little rubber boots on the towers do not make a100% moisture proof seal.
TRUE GRIT |
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Marty Levenson (05-14-2017) |
#16
IP: 71.178.88.35
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ALMOST THERE!
Marty...compression = good, fuel on plugs = good, spark = good, but still won't run..now is the time to re-check timing. I recommend you start from scratch to make sure it is set correctly.
Teach them how to set the motor to TDC (can you access the front of the motor to turn by hand/view roll pin?) and then make sure the rotor is pointed at #1. One tooth off on the distributor gear will make it very difficult to start/run. We just went thru this procedure with my buddy's C-30 a couple weeks ago, and all three of us that were there are gear heads, but, it finally ran after setting timing from scratch. If you get it all lined up, you can adjust the distributor while cranking, just watch out for moving parts, or move it a little and lock it down in between each attempt until it fires. After some run time, you can set the timing for cruise RPM. One last check, especially since it is EI, make sure the dizzy weights under the EI plate are free!
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-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!!) Last edited by sastanley; 05-14-2017 at 11:29 AM. |
#18
IP: 50.92.238.107
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spark
Thanks - want to get a good spark first. Then timing!
Pretty sure not the coil or battery....how could one plug have a blue spark otherwise? Likely connections to distributor towers or plugs, ign wires, gap on plugs, or plugs themselves (least likely: new) ....
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Marty 1967 Tartan 27 Bowen Island, BC |
#19
IP: 206.74.103.31
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Spark plug firing order
Marty, just a reminder - since the distributor cap was removed - have them check for the correct firing order on the plug wires
Rick |
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sastanley (05-14-2017) |
#20
IP: 76.7.103.223
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Post 13 "yellow spark at three cylinders, and a whiter spark at one"
Post 18 "one plug have a blue spark" I'm confused. I can say that when my coil failed I had weak/yellow spark and a non-starting A-4. With a new coil the spark was blue and strong with instant start up. A world of difference. Dan S/V Marian Claire |
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sastanley (05-14-2017) |
#21
IP: 98.171.161.182
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I don't trust the "mechanic" that worked on the engine previously.
If by any chance the spark plug wires are graphite core not solid core toss them and replace them with solid core wires. TRUE GRIT |
#22
IP: 50.92.238.107
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update
Thanks for your replies.
I spent some time at the boat today, and also had a chance to speak with the mechanic. He stated that his compression test two months ago was very low (35 - 70) and a wet comp test brought the numbers up a little. But now we get good numbers (85 - 100) on a cold, dry test. I do believe him: he has a solid reputation on our island, and just seemed real. Even added that he calibrated his compression gauge and rechecked. Wondering if the oil he put in the cylinders and/or more cranking loosened up the valves? I have not messed with the valves directly as the compression seems good enough to allow the engine to start. I never saw a good spark, though all plugs had yellow spark. The batteries were very low, so it hardly cranked. My plan is to charge both batteries fully, change the coil, and give it a try. The wires seem to be in the correct order (1243), and we used my spare wires, which I know worked last time they were deployed.Plugs look new and are now gapped. Ignition is electronic. To repeat, rotor and cap are good, known spares. Gas is getting to the plugs. The carb was rebuilt recently. Frustrating but nothing to do without batteries: they are on a government dock with no power available so charging the batteries at home.
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Marty 1967 Tartan 27 Bowen Island, BC |
#23
IP: 142.52.197.129
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Hi all,
I am the co-owner of the C & C 33 and its Atomic-4! Thanks for all your replies. It is very helpful for beginners like us. And a special thanks to Marty who learned a lot while we did not even know how to start it (or try to). As Marty said here, the compression looks fine (80-100 psi) and spark plugs smell gas. The battery looks pretty low and we charged it for about 4 hours with a 2A charger. We could not load it more as there is no electricity at the dock and we had to leave the island where the boat is. After that, when we tried to start it, it ran pretty fast as if it almost started but then, after 20-30 seconds that we had begun to push the starter button, it brutally slowed down while we were still pushing on the starter button. We tried 3-4 times and always the same behavior. Do you think it is just because of the low battery or it can also comes from the ignition system ? |
#24
IP: 98.171.161.182
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Quote:
Maybe the reason the mechanic got low compression numbers is because the battery was not charged adequately? TRUE GRIT |
The Following User Says Thank You to JOHN COOKSON For This Useful Post: | ||
Marty Levenson (05-16-2017) |
#25
IP: 50.92.238.107
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Plugs
Found the answer to the below question. (Robert Hess's old site)
Still helping the new boat owners. While the batteries are getting an extended charge I pulled the plugs to check the gap. They are NGK BR6S. I looked up Atomic 4 on the NGK site and find they list B6S (no "R") for the A4. Anyone have experience with these plugs - are they compatible? Thanks!
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Marty 1967 Tartan 27 Bowen Island, BC Last edited by Marty Levenson; 05-19-2017 at 10:06 AM. Reason: found new info |
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