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  #1   IP: 134.134.139.76
Old 06-03-2018, 08:22 PM
ronstory ronstory is offline
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Unhappy A Puzzle: Engine seems to be running rich or burning oil but has good compression

I have a new to me A4 out of a freshwater sailboat that has been converted to fresh water cooling. The old engine was having challenges with oil pressure and even after adjusting the oil pressure to 60 PSI at idle it would drop to 10 at when hot at idle so I jumped on the newer A4.

It was in visually just about perfect shape, no rust and looked to have little use. The folks just used the engine to get clear of the dock and to return to the slip. The compression was 110 psi on cylinder 1-3 and 90 psi on #4 and it didn't improve with a squirt of oil. The lead to me that one of the valve seats may be touchy, and I'm not sure overall accuracy of the compression tester since we used the seller's, but nice older Craftman, before Sears sold out.

I installed tne 'new' A4 and I seem to have a problem with smokey exhaust. First thing, i took the carb apart and cleaned it and that helped with starting but I had problems with a bit engine RPM varying and idle or under consistent throttle setting. Not horrible, but annoying. Since I don't know a ton about this engine, I spurged on a new carb from Ken at MMI and installed it this weekend plus the engine came with the Indigo PCV kit. I also replaced the plugs with with the RJ12C (0.035" gap) and notice when I pulled the old spark plugs the were all uniformly sooty, with the #4 cylinder spark plugs was 'moist' a touch of oil on it.

So I squirted a bit of MMO into each cylinder as it replaced the plugs and let it sit for an hour or so before starting. Got the traditional whiteish smoke and then settled down to looking like it was running a bit rich but better than with the old carb and plugs. I adjusted the carb in about a half turn for 1 turn out from seat. That seems to be where it idled the best.

Next, I dug into the distributor removed the Pertronix base plate and checked the advance mechanism. Nothing stuck and everything moves, but the advanced springs seem pretty light, I could easily turn the rotor by hand and max out the advance ... but I'm not an expert.

I then timed the engine at 1800 RPM tied at the dock and got the highest RPM and backed off a touch. It's maybe a a bit better on the exhaust smoke but more than it should. At this point the engine starts perfect with the new carb, no idle creep (one thing fixed! ) and has been run for about 30 mins since the carb install.

So being curious, I pull the spark plugs and they all looked just like the old plugs! All were sooty and a bit moist on #4. The boat is 2+ hour from home so I put about an 1oz of MMO in each cylinder, reinstalled the plugs, pulled the coil wire and 'bumped the starter' to help toss the MMO around head/valves... reinstalled the coil wire and drove home.

I'm hoping the MMO will help clean/loosen something... but I'm grasping at straws. I was not expecting sooty spark plugs after 30 mins of operation.

Any other wisdom, thoughts and/or ideas?

Thanks,
Ron
Portland, OR
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  #2   IP: 24.152.132.140
Old 06-03-2018, 08:48 PM
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Here come the questions

  • What color is the exhaust smoke?
  • Do you use fuel additive(s)?
  • Why the PCV? Is it needed (excessive blowby)?
  • If your first plugs showed a rich mixture, why richen the mixture further with the new carburetor (turning the mixture screw in richens the mix)?
  • Is a precise timing exercise possible (as opposed to timing by feel)? By possible I mean do you have the means/tooling to precisely find #1 TDC, i.e., MMI crankshaft timing tool or precision measuring equipment, timing light. Do you have the means to make a precise timing mark (as opposed to the crankshaft roll pin)?
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1977 Catalina 30
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prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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Old 06-03-2018, 11:50 PM
ronstory ronstory is offline
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Hi Neil and thanks for help.

Answers inline below:

Quote:
Originally Posted by ndutton View Post
  • What color is the exhaust smoke?
    rns> The classic wisp of blue smoke, similar to what you get out of an old school 2-stroke motorcycle. It the A4 was a 2-stoke, I'd be done.
  • Do you use fuel additive(s)?
    rns> Just Sta-bil fuel stabilizer, no MMO or Seafoam.
  • Why the PCV? Is it needed (excessive blowby)?
    rns> The motor came with the PCV. The previous owner he had some smoke in the cabin and adding the PCV cleaned up the problem. When I first got he motor out in the harbor, I had smoke coming out the oil cap breather but the motor had sat for for 6 months so added a quart of the MMO to the oil and after two hours of running that problem seem tamed, but have not done extensive motoring on this motor so far, so there could still be a problem.
  • If your first plugs showed a rich mixture, why richen the mixture further with the new carburetor (turning the mixture screw in richens the mix)?
    rns> Doh. I turned in the mixture screw closer to the seat, and by your question just remembered the mixture controls air and not fuel. (sigh) I knew that at one time but was in a hurry to get home and avoid traffic.
  • Is a precise timing exercise possible (as opposed to timing by feel)? By possible I mean do you have the means/tooling to precisely find #1 TDC, i.e., MMI crankshaft timing tool or precision measuring equipment, timing light. Do you have the means to make a precise timing mark (as opposed to the crankshaft roll pin)?
    rns> I have a piston stop, but could not locate my "vintage hand crank" so did it by feel while running under load. The piston stop would allow me determine TDC rotating both ways and than halving the position. However, my hand crank is really only good at turn the motor CCW direction to start Need to make a jig or just buy the rotation tool from MMI.

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  #4   IP: 104.156.210.130
Old 06-04-2018, 09:27 AM
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I think we can agree your engine is showing signs of internal wear. There are a few things you can try to minimize the symptoms however:

Fuel/Air mixture
Try adjusting the mix to a smooth idle with the adjustment screw as far out as possible. In other words, adjust to the leanest setting that delivers a smooth idle.

Timing
Set the timing precisely. Power timing tends to err on the advanced side which can increase blowby. You report that you have the tools to find Top Dead Center accurately but you should create your own timing mark for timing light use. Thatch on this forum is passionate about timing and has come up with a couple of timing mark methods that are much more accurate and easier to use than the crankshaft roll pin. If you have a sheet metal flywheel cover, here's a picture of one of his methods. With the window and notch cut in the cover, mark the flywheel with a white paint line so the marks align at #1 Top Dead Center. With these marks, set the timing at idle (assuring no advance influence) with a timing light. Moyer has a timing handle (different from the hand starting crank) where the handle is aligned with the crankshaft roll pin. It moves the crankshaft both directions. https://moyermarine.com/product/igni...misc_01-1_285/

Name:  Flywheel cover.jpg
Views: 222
Size:  185.6 KB


Another method is an accessory drive pointer. It is fabricated from 2 hose clamps. I have this and it works well.
Name:  A4 timing pointer closeup.jpg
Views: 220
Size:  125.7 KB


Addition of top oil in the cylinders
Unless you've had a water incursion or are dealing with sticky valves, I'd lay off the Marvel Mystery Oil treatments for now. It is certainly contributing to your exhaust smoke. It would be interesting to see how much of the smoke is from the engine and how much is from your oil treatments.
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1977 Catalina 30
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prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others

Last edited by ndutton; 06-04-2018 at 09:29 AM.
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  #5   IP: 108.172.150.97
Old 06-04-2018, 10:46 AM
Marty Levenson Marty Levenson is offline
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lean = in?

"Fuel/Air mixture
Try adjusting the mix to a smooth idle with the adjustment screw as far out as possible. In other words, adjust to the leanest setting that delivers a smooth idle."

I thought to screw the mix screw IN was LEAN....?
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Old 06-04-2018, 10:48 AM
Marty Levenson
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  #6   IP: 104.156.210.130
Old 06-04-2018, 10:57 AM
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The screw adjusts air, not fuel. Adjusting out allows more air into the mix.
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1977 Catalina 30
San Pedro, California
prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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  #7   IP: 192.55.54.42
Old 06-04-2018, 11:23 PM
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Neil--

Sorry for the delay, a work Monday interfered.

The good news about this motor is that it actually has oil pressure after running hot. Plus it is not a rust bucket.

Yes, my belief is that the motor sat for a while and got a bit caked up. In my experience after recovering with friends *too* many international harvester scouts & travel-alls from many years neglect under actual trees.... I'll let the MMO sit for a bit longer... then run for an hour or so and then change the oil. IMO, IH motors and A4 seem to be from a similar cloth regarding low compression and low RPM designs... and MMO is a wonderful tonic for maligned IH motors. Plus reading Don's archived newsletters on MMO for an actual engine flush, I have a bit of (justified) hope.

All--

Is there a thread on how to add a timing port on the flywheel cover of the engine? What I've found to date is a a photo or two of with a cover and slot cut into it. I'll use the the piston stop to gather the interference degrees and then map that back to TDC.

Thanks,
Ron
Portland, OR

Last edited by ronstory; 06-04-2018 at 11:42 PM.
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  #8   IP: 24.152.132.140
Old 06-05-2018, 12:02 AM
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I didn't mean to discount MMO as the true mystery it is, just that if you're going to use it you can expect some exhaust smoke.
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1977 Catalina 30
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prior boats 1987 Westsail 32, 1970 Catalina 22
Had my hands in a few others
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Old 06-05-2018, 01:38 PM
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Ron,
Sounds to me like your piston rings (particularly the lower oil control rings) are showing wear.
One thing that might help your present situation is to install the adjustable main jet (available from our host). This would allow you to run things a bit leaner.
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Old 06-05-2018, 03:59 PM
ronstory ronstory is offline
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Good idea, I have the MMI adjustable main jetbut did not install it since I wanted a nice solid baseline on the new carb. I need to look at the old A4 in the garage to see where the best place it to install a timing slot.

Thanks,
Ron
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Old 06-06-2018, 03:09 PM
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Remember, to make the mixture leaner, turn the idle screw out, or the adjustable main jet in. I get confused about this, so I made a little note and posted it near the engine. Turning the idle screw out gives it more air, turning the adjustable main jet in restricts the gas. I had no problems with the standard main jet, but the adjustable one is nice to have. Once I was leaving the marina and the engine was not running right with a load, and sounded like it might shutdown. There was no time to adjust the timing while navigating the marina, but enriching the mixture with the adjustable jet made it run better. The trouble with the adjustable jet is you have to adjust it right.
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Old 06-10-2018, 11:34 AM
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Thanks all for the suggestions and pointers.

Last weekend I apparently managed to bump the battery charger circuit breaker so I got an alarm from my boat command monitor. That made me paranoid since I just rejiggered the battery compartment and to moved the cables out of the way of the new 3rd battery. Could I wired something wrong? Not likely, since a senior tech once pounded into me "With power, never trust a label/color, always measure". But I'm paranoid.

It turned out to just be a flipped breaker but while I was there I played around with A4 and carb. A week ago, I had put 3/4 oz of MMO in each cylinder, bumped the starter to splash it around. So when I started it I got the MMO smoke signal for a about 10 mins. I adjusted the idle jet *out* this time and got a nice idle with no stumble off idle about 2.5 turns out.

I let the motor run at about 1100 RPM for another 10 mins until the oil was fully warmed PSI dropped to 20 at idle . I then did an in-gear a load test in gear and everything still seem to be working fine. There is still a bit more blue smoke that I like, but I need to tackle my timing next time.

Now the weird thing. After the MMO treatment, would swear the motor is quieter at idle. it didn't sound bad before, but now it just seems more sewing machine like and i can hear the faint noise of the value train which I don't remember hearing before. Just a another oddity.

Thanks,
Ron
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  #13   IP: 107.77.70.58
Old 06-11-2018, 07:36 PM
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Not odd to me. MMO makes the valves operate more smoothly. Mine are easily demonstrated to stick a bit without it.
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Old 06-13-2018, 11:37 PM
ronstory ronstory is offline
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Great to know that I'm not hallucinating.
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Ron
Portland, OR
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