No Compression in #4

[chrisoelder]

Hi All!

I have a small issue that I noticed yesterday while out. I noticed that the engine seemed to be having some trouble at the base RPM. She would only stall when in gear and throttling up (not every time). After the sail, I started to do some basic troubleshooting and realized I have zero compression in the #4 spark plug. This would make sense why the engine seems to be struggling a bit. Did some research here and determined that my valve must be stuck open. I tried a bit of oil and WD40 but no luck. Still no compression. I ran out and grabbed some MMO to give that a try this week but wanted to reach out here and see if you guys had any other theories or ideas of how to resolve this compression issue.

I have been thinking about giving the engine an acid rinse, do you think that could help with the valve?

A week before this last sail I did a tune-up: Changed the fuel separator, replaced spark plugs, replaced the raw water impeller, and gave her an oil change. I topped off the fuel separator with a bit of seafoam and added a bit of MMO to my oil change. Not sure if this info is important but wanted to share incase

Thanks!

[Dave Neptune]

First an "acid flush" would have absolutely nothing to do with the valve.

Sounds just like a stuck valve. Often you can get the valve loose by using an allen wrench to move the valve through the plug hole or remove the side plate and get it loose that way. But first try "spraying" into the cylinder while cranking the engine with the water valve and ignition off. let the oil soak and repeat a few times over a couple of days.

Now to the fuel. How much and what additives have you mixed into the fuel?

Adding some TCW-3 (best) or MMO to the fuel and running her for a bit will often "shake" the valve loose and the oil in the fuel will get "on the valve stems" and clean things up after some hours of running. Don't use to much or many products. I mix the lubricants into the fuel at around 100:1 or a bit richer.

Dave Neptune

[chrisoelder]

@Dave Neptune - thank you for the quick reply!

RE: Acid Flush, excellent! Good to know!

When you spray into the cylinders are you only using oil or are you using a mixture of ATF and oil? Possibly some Acetone to help remove any possible carbon build-up?

Excuse this dumb question: when you say spraying you are saying to put a small amount of oil in the plughole. not actually spray oil into the plug hole right?

I haven't added any lubricants to the fuel since I found the issue but I am planning on doing that. I normally add a small splash of MMO when filling the tank.

[Dave Neptune]

Yes, use a spray and spray directly in and towards the valves. The spray will get to the "valve stems" better than just pouring some in. Any good spray lube WD-40, Tri-flo, garage door oil or pretty much any spray lube. Do spray towards the valves and if you can crank the engine at the same time do so. Also use a rag to catch the bit of spray being shoved out of the cylinder when cranking.

Hint, do remove all of the plugs so the engine will spin faster on the starter. ONLY spray into the offending cylinder so starting will be easier without the other 3 plugs having to deal with burning all that was sprayed in, when ready to try.

It may take a few cycles of the above but they will usually get loose with patience.

Dave Neptune

[chrisoelder]

Excellent! Thank you for the breakdown. I am going to give this a try over the next week.

I will let you know how it goes and if I can get some compression

Thanks!

[Dave Neptune]

Since your fuel is just fuel go ahead and add some TCW-3 (2 stroke synthetic grade) or MMO guess your fuel in the tank and add enough "top oil" to get a bit richer than 100:1, it won't smoke and it's also very good for the rings while keeping oil on the valve stems, a good thing.

I ran my engine with TCW-3 for over 30 years and didn't loose any performance or a drop in compression numbers in fact they did go up a bit.

Dave Neptune

[chrisoelder]

Excellent Thank you @Dave!

My tank is 15 gallons I plan to add 19.2 Ounces every time I fill her up. I'm excited to get down there tonight and get cranking haha

[chrisoelder]

UPDATE

Went down to the boat this evening for a few hours. Spent some time hand-cranking the engine and spraying a bunch of wd-40, garage door lubricant, and a bit of MMO into the plug hole. I also added in the MMO to my fuel to give that a try

@Dave those hints were an arm saver when cranking thank you haha!


Observations

1. When looking into the plug hole while cranking I could see one of the two valves (the valves closest to plug #3 - I believe it's the first #4 valve) moving but I couldn't see the other one. I had an Allen wrench and couldn't feel anything raised (or lowering when cranking) when the other valve was lowered. I wonder if it's stuck closed? Is that a possibility?
2. After hand cranking for a bit and almost a can of WD-40 I attempted the "thumb" compression test. Obviously, #1 thru #3 all had compression but #4 still didn't, I did hear some gurgling when cranking and pressing my thumb on the plug hole. Not sure if the gurgling means anything other than there was a bunch of liquid in the valve chamber
3. After I decided to run the engine for about 30-45 mins in an attempt to have the MMO I added to the fuel run through the engine. The engine started up pretty good and didn't stall when going in and out of gear and throttling up. When throttling up I did notice that now there is a tapping happening that wasn't there yesterday. Which makes me think I have a valve tapping. Not sure if the hand-cranking and spraying helped but maybe it's getting it a bit looser? I recorded some audio of my A4 at idle, throttling, then back to idle for reference
   https://drive.google.com/file/d/1F0e...ew?usp=sharing Sorry for the quality at the end, after throttling up I grabbed my phone and I think I covered the mic when returning to idle

Currently, I have MMO, garage door lubricant, and WD-40 sitting in the valve chamber. Planning on heading back down tomorrow to keep on spraying and cranking with a heavier duty penetrating version of the WD-40

Do my observations change the problem/solution at all? Let me know what you think!

Thank you all!

[Dave Neptune]

whoa a little

When suggesting a lube I meant any one of those or basically any spray lube. Also by "cranking" I meant with the starter motor and the ignition off as well as the water valve closed.

Now hearing a tapping when running is good as it means the valve is starting to drop back into contact with the cam IE movement. The valve can stick anywhere on the way down to the seat so the cam can push it a bit unless it is stuck at the very top. If the valve is actually stuck in the middle somewhere and I mean stuck the valve will bend or break. Sounds like you have "motion" so bare with it.

The shaking of the engine when "running" will also help to shake the valve loose as oil is getting to the stem and the valve tappet is now contacting the cam and this motion should increase over a bit of time, patience.

Also flooding the cylinder with oil is a bit much. IE a whole can of spray should last for many many spritzes. It is the spritz that gets on the stem as well as the oil in the fuel when running.

Order: spray a spritz while the engine is cranking on the starter then let it sit for a while, say one spritz every hour or so. Then fire her up to let it shake around and warm up~~then cool crank and spray.

If you don't have a remote start switch get one or make one up, it's a cheap and very handy tool. I mounted one permanently on my engine and I've done so on many others for friends.

Dave Neptune

[chrisoelder]

Thank you, Dave! Sorry for my confusion, not sure why I thought you meant hand-cranking but it was cool to see it all work slowly. I am going to pick up the remote starter this evening!

I really appreciate the breakdown! I am going to head back down tonight and use the remote starter.

I will let you know how it goes! I love this stuff, learning so much

Thank you!

[Hawkeye54]

That's the attitude needed here

Chrisoelder, you have the right, positive attitude for working on the Atomic 4, and you are obviously learning lots as you proceed !!!



Rick

[chrisoelder]

Nothing major to report

UPDATE

Went down last night and followed Dave's instructions! Everything went very well. I can hear more tapping now, even at a lower RPM. Making progress, going to head back down over the next few days to keep working on her.

I really like the remote starter, that was a great $15 purchase.

Thank you all!

[ronstory]

Progress is a great feeling. ;^)

Soon you will have much healthier A4, especially with Professor Neptune's wisdom.

[GregH]

.. Professor Neptune's wisdom.

A very Steampunk name.

Buy the latest elixir!
Increase your brain power!
Buy Professor Neptune's Wisdom elixir!

[ronstory]

it was either that... or "Mr. Wizard".