Glad to be here!

[rgarrett22@hotmail.com]

Having a few issues with my A4 and so glad to have a community forum to troubleshoot problems with others. Recently had it rebuilt by a professional marine mechanic and it smokes out the exhaust as much now as it did before the rebuild! When I asked him why, he stated that the valves on a rebuilt A4 tend to stick so be bores out the valve guides to help prevent this. Anyone out there heard of this before?

[Dave Neptune]

Smokin'

rgarrett22, first welcome to the MMI Forum.

Yes I have seen that done on more than one engine but no experience with anyone on the A-4. It was common practice to leave a bit more clearance on the exhaust valves for the same reason. The question is how much did he open them up and how did he do it. Excessive smoke on a flathead is usually not from the valve train or at least not nearly as much as an overhead can. Gravity works to keep the flathead oil running back down and in an overhead gravity is pulling it into the cylinders.

Have you done compression check? How do the plugs look?

Dave Neptune

[Marian Claire]

Another welcome. How many hours on the rebuild and at what temp? Just wondering if the rings have had time to seat properly.
Dan S/V Marian Claire

[67c&ccorv]

Having a few issues with my A4 and so glad to have a community forum to troubleshoot problems with others. Recently had it rebuilt by a professional marine mechanic and it smokes out the exhaust as much now as it did before the rebuild! When I asked him why, he stated that the valves on a rebuilt A4 tend to stick so be bores out the valve guides to help prevent this. Anyone out there heard of this before?

Yep - that's a great way to dump a lot of oil into the combustion chamber.

So - how do we know he is a "professional marine mechanic" with experience on the Atomic 4?

[lat 64]

Welcome.

It's like Dave said, Machinists have several ways of "helping" a valve to not stick. I admit years ago I gave some abused dirt-track Chevy race engines a tad more clearance on the exhaust valves, but not anything that shows up as oil consumption or smoke problems. The preferred method from this Atomic-4 crowd it seems, is to use proper lube and run the engine regularly.

Many of us have to accept less than ideal clearances when fixing our boat motor for time or budget concerns. Everyone's case is different so some old engines smoke a bit and that's ok for that person. But…

You hired a pro.
It sounds like your mechanic was not even surprised about the smoke. Q: Is it true that he offered no other ideas except that his machine work was the reason for the smoke?
It's a four-stroke, it's not supposed to smoke. A properly rebuilt engine, even just a re-ring overhaul, will just puff a bit when first fired up if it was done within manufacture's spec.


There is some hope that the smoke is from a different source. Some ideas I come up with are:

* still lots of oil in the exhaust system
* assembly lube was used too liberally and is still burning out.
* Carb set too rich
* Diesel fuel in gasoline tank
* smoke is actaully water vapor or a combination of things.
* compression rings were bent while being installed and will eventually wear in.

Russ

[rgarrett22@hotmail.com]

Thanks to everyone for the welcome!!

Sorry to reply so late to all of you're kind responses. He never changed any of the piston rings as he stated the compression was good. The engine would have 15-20 hours of run time since the rebuild. The transom of my boat is covered in black soot. It starts well every time (as it did before). It just smokes too much for my liking. As you said it is a four stroke and should not smoke. The plugs are covered in black carbon and cylinder 1 and 3 are wet. And that's after it was leaned out!! I've thought of putting in a hotter plug to see if that helps as I upgraded the ignition system to electronic. I'm thinking of pulling the engine again this fall and having it again rebuilt by some one else reputable and see if what was stated to be done was done. The mechanic I used has been around a long time and services the boats in several large marinas. He was the most reputable or so I thought.

[lat 64]

Smoke—black, white or gray?

Black smoke is a good sign!
If it is really black soot, then this may be a fuel problem. There are so many variables to sift through for proper diagnosis. Can you give us more detailed info on just how the carb is set up?
We could guess around here for weeks but I bet we could zero in on the problem if you can describe exactly how it runs, start technique etc..

Confiscate* your kids smartphone and take some video of the engine running and post it on u-tube.
Can you snap some photos of the throttle linkage too? That much black smoke I'm starting to think it may be a choke problem. Perhaps choke is still partially on when you think it is not.

Let's not forget that these engines run on three and sometimes just two cylinders. Could be spark is gone in #1 & #3? Raw gas from dead holes mixing in the exhaust would make pretty icky smoke I think.

Also, can you smell anything like….wait for it….Diesel?

Let us take a crack at it,
Russ

* Don't use your own, you might drop it in the harbor.

[lat 64]

Can anyone else tell me if overfilling the crankcase with too much oil would cause any of these symptoms he is suffering from?

[Dave Neptune]

+ oil

Russ, I run my boat at about 1/2 to 1 Qt. "overfull" and never seen an oil issue. My engine is 44 years old and runs clean on stock plugs. I have never had a fouled plug in this engine.
I kinda side with you regarding the choke until we know otherwise. If a vent well in the carb was lugged a bit that would certainly richen it up too.

rgarrett, have you tried putting the plugs in different cylinders to confirm it's the cylinder and not a bad plug? Also what are you gapping your plugs to?

Dave Neptune

[JOHN COOKSON]

covered in black carbon and cylinder 1 and 3 are wet. And that's after it was leaned out!!

Are wet with what? Water or fuel?
Perhaps intermittent firing because of water in the fuel or an ignition system problem?
BTW - I didn't reread the thread. Has a comperssion check been done recently?

TRUE GRIT

[lat 64]

Are wet with what? Water or fuel?
Perhaps intermittent firing because of water in the fuel or an ignition system problem?
BTW - I didn't reread the thread. Has a comperssion check been done recently?

TRUE GRIT

He only said that the mechanic said it was "good". We got no numbers yet.

rgarrett22,
You have the attention of the brain trust now, so bury us in data.

[hanleyclifford]

It always makes me cringe a little when I hear about opening up valve guides to get more clearance. Did the mechanic tell you what clearance he opened them to? The factory spec was .002-.003 and Don Moyer allows another .001 to .004. But remember that is on new guides. What was the condition of your valves? How many were replaced? There can be variation on stem ODs along their length that is scary.

[lat 64]

Hanley's post got me thinking that Mr. R. Garrett will not know or have access to much of the detailed info we want to make some predictions and be helpful to diagnose this smoke problem. His mechanic was not forthcoming with much.
This is not a deal breaker.

It's like this rgarrett, we would like to have you be our eyes and ears to the symptoms of the engine and it's running. Just like the car talk guys.
So, the more you ramble and tell the story, the more clues we can get to the problemo.
This is typical troubleshooting, it's full of forks-in-the-road. The first and most important is: the question: What is the smoke?
(1) Is it unburned fuel?
(2) Is it lube oil from the crankcase?
or
(3) is it steam and vapor from the cooling system?

You wrote:

"..The transom of my boat is covered in black soot. It starts well every time (as it did before). It just smokes too much for my liking. As you said it is a four stroke and should not smoke. The plugs are covered in black carbon and cylinder 1 and 3 are wet…"

Smell the smoke. look closely at the soot, even taste it if you are past your child-producing years and give us some impressions of what you are "seeing".

I'm getting ahead here but, the next question is: Did anyone clean or rebuild the carb? Was is done correctly?

[rgarrett22@hotmail.com]

You guys are awesome!!

Thanks for all the attention to this matter. This is my first time using a forum and I wish I had of put my name (Randy) instead of my email address!! Didn't realize it would come up that way.

This engine has worked consistently all it's years since 1973 and has around 4000 hrs on it (since my dad put an hour meter on it). It always smoked a tad but tolerable amount prior to the rebuild. I had to take it out to service the transmission as the lock pin in the adjustment casting had a crack in it. So while it was out I thought lets freshen up the old girl with a rebuild. I wish I knew of this forum and Moyer Marine as I would have preferred to do an exchange for the extra $ and would have had peace of mind!!

For an FYI here is what was stated done and the related cost. 4 plugs $30, carb kit $69, machining $980, gasket set complete $475, ignition module $265, coil $69, impeller $48, main bearing $289, cam bearing $178, rod bearing $198, 8 valve guides $318, 4 intake valves $175, 4 exhaust valves $192, shop labour $1140. Plus the cost of taking the engine out then back in. Total bill = $4344.

It should not smoke!!

I'm not getting the service after the sale from this fellow just excuses, which makes me suspicious.

This weekend I will video the smoking along with what the transom looks like.

Thanks everyone.

Randy

[ndutton]

Oh my!!

Ouch - - - ouch - - - OUCH!!

You're right, for $4300 it should not be smoking. However, your only remedy is through this guy and so far it's not looking good. That's a big part of Moyer's value, after sale service.

Man, I can't breathe. Full gasket set for $475?? I just bought one from Moyer. Out of respect for what you're going through I'll avoid mentioning the price. Ignition module $265?? I can't look anymore.

Welcome to the forum Randy. We'll take better care of you.