Just Another Power Loss Issue

[Bruce A]

Hi Jerry,

My Atomic 4 is vintage 1969 and I doubt that the distributor has been rotated in twenty years (if ever) which is probably why it is stuck. Checking timing using a timing light does yields the correct specified advance (17-18 degrees) although I realize that their may be some subtle difference at full power. I checked the advance weights and they are not frozen and seem to be operating normally. What bothers me the most is the apparent super rich condition at WOT (fuel puddling in carb throat).

As usual, access to the distributor to force it to rotate is not available. I thought maybe someone has had to deal with this problem and may have a magic bullet.

I just realized that I did not report on the "engine stalling problem" in my original post (also neglected to mention it in the post yesterday). This was the solution (maybe a dual solution):

1. The coil that was installed on the engine was one that required an external ballast and it was drawing a lot of current because their was NO external ballast in the system. I purchased a NAPA coil, as recommecnd in this forum, which did NOT required external ballast. As a result primary current levels went way down and so probably I have a much cooler running coil.

2. At the same time as replacing the coil, (1 above), I also cleaned all the contacts in the primary circuit.

After doing the two steps above I have not had ANY engine shutdown problems with about 15 hours on the engine, HORRAY!

Bruce

[roadnsky]

Just for laughs I tightened down on the idle adjusting screw as this is the only adjustment available and I just had to do something! RPM's increased to 1700 (but no more) and speed to 6.3 kts. The puddle still formed at WOT. This is a minor improvement but I just replaced the prop with an indigo three blade and Tom Stevens said that I should be able to cruise at 2000 RPM and push to 2400 RPM with his prop (assuming the Atomic4 is in reasonbly good shape).

John-
Just reading thru your post again and saw another "maybe"...
Just to be clear, are you sure you were turning the IDLE ADJUSTMENT and not the IDLE MIXTURE?
Also, do you have an ADJUSTABLE MAIN JET?

Please don't be insulted by the question. Just trying to be "Devil's Advocate" and stir the thought juices a little...
(see attached)

[Bruce A]

Hi Jerry,

Sorry, it was the "Idle Mixture" that I adjusted (turned adjusting screw clockwise). I do not have an adjustable main jet.

Thanks for being the Devil's advocate---we need more Devils.

Bruce

[ghaegele]

Bruce, does the distributor cap rotate a few degrees when you twist it clockwise (I think)? That's the timing advance for higher RPM. If that's not working it would effect performance at higher RPM.

Greg

[sastanley]

Bruce,
This topic comes up periodically and I am still curious. How do you guys check your timing with a light? Do you take off the flywheel cover? How do you have access to the flywheel? Did you make your own marks?

I have a Catalina 30,and think I am S.O.L. on the timing check with a light (however, I have pretty good access to the distributor and could spray the contact area with PB Blaster, etc.. & put a pipe wrench on it to knock it loose if it was stuck.) Even even though it is running well, and I cleaned my timing advance weights this winter, I'd still like to check things like timing with a light if I could figure out how to do it.

[Bruce A]

Hi Greg,

The distributor cap is screwed directly to the distributor body so I don't think it can rotate even under normal conditions. However, as I recall the rotor itself (inside the distributor) does rotate to provide a mechanical advance. The rotation is controlled by the advance weights. This mechanism does work properly. I think that it is just a case where the distributor body has bonded itself to the large mounting hole drilled in the accessory drive to accept the distributor. I haven't squirted it with PB Blaster yet as I am not sure what that will do to the aluminum body, plastic cap etc.

Let me know if I am wrong about the cap rotation. Because as I remember on my distributor the cap does not rotate---if it is suppose to then I definitely have a problem. I will be at the boat later today and will double check the issue.

Thanks,

Bruce

[Bruce A]

Hi Shawn,

It is very easy on my Atomic four to check the timing with a light. My flywheel cover is "right in my face" and the end of the crank is visible through a hole in the cover. The end of the crankshaft has a roll pin installed which indicates zero degrees advance when it is vertical (as I recall there is mark on the flywheel cover to make this obvious). I use a protractor to make a mark on the flywheel cover 17 degrees clockwise from the vertical position. Then I connect the timing light to a power source (if you have an old one like mine it requires a +12 VDC source--some of the new ones get power from the spark itself) then connect the timing light high tension lead to #1 spark plug. When you make your obervation, at 1600 RPM, the roll pin will line up with the 17 degree mark if that is were your distributor is set. In my case the roll pin and my mark lined up perfectly--however as I have read on the forums the specified 17 degree advance that we normally check without a load may require adjustment under load to get full power. My distributor is stuck so I cannot play around with the timing adjustment until I figure out how to unstick it.

I am somewhat familiar with the Catalina 30 engine layout and you may have access problems when it comes to getting to the flywheel cover to make the marks and actually see the rollpin/mark while running the engine.

Hope this helps.

Bruce

[sastanley]

wow! how simple!

Bruce...it helps immensely. Thanks. I never thought about putting a mark down near the center of the cover!

I have already drilled a small (1/2") hole in the boat in front of the flywheel where the roll pin is. When I put the engine back together this spring, I had removed the dizzy for cleaning & electronic upgrade. Upon assembly I realized I had no idea where TDC was, so I drilled the hole to shine a small flashlight onto the roll pin, so could see it with an inspection mirror, which clarified my guess using the compression on #1 trick.

Sounds like I just need a larger hole that I can plug up with something that doesn't look too bad afterwards.

Thanks, sorry to hijack your thread

[roadnsky]

In my case the roll pin and my mark lined up perfectly--however as I have read on the forums the specified 17 degree advance that we normally check without a load may require adjustment under load to get full power. My distributor is stuck so I cannot play around with the timing adjustment until I figure out how to unstick it.

Bruce-
Man, I'm really thinking this is your limited RPM/power issue.
It just makes sense that you need a bit more adjustment on the distributer while under load.
Anyone else have any ideas?

[ghaegele]

the rotor itself (inside the distributor) does rotate to provide a mechanical advance.

Oops... that's exactly what I was talking about. That's what you get for 2 cents! Sorry it wasn't that simple.

[Bruce A]

Fuel Problem Update:

I was able to "unstick" my distributor with elbow grease, PB Blaster, various other penetrating lubes and Robo locking pliers. I removed the distributor for inspection and the surfaces that rub against the accessory drive hole were covered with crud (almost resembled epoxy it was so hard). Once cleaned up and reinstalled the distributor rotates easily.

When adjusting the distributor position under load I could not get the RPM's to increase (other than maybe 25 RPM at best) so my timing was already set properly.

I did notice that after moving the distributor to pick up the added 25 RPM's and locking it down at this point the idle had changed sightly so I readjusted the idle mixture. This work was done day before yesterday. We went for a sail yesterday and while we were motor/sailing out of the harbor with the engine at idle or maybe 1000 RPM it died. I smelled gas and after removing the flame arrester I saw the infamous pool of fuel in the carb intake throat. The engine was completely flooded and would not start (luckily we were under sail and it really did not matter for the moment). After sailing for 4 hours the engine started right up and I keep the RMP's up until we were docked at the slip. While observing the intake throat and reducing the idle to typical 800-900 RPM fuel started to run down the inside of the throat and collect at the bottom of the intake eventually bogging down the engine and it quite.

So things are going from not so good to worse. My question is can minor resetting of the idle mixture adjustment cause this radical flooding? Or maybe it is just coincidental and the float took this moment to get stuck. I would appreciate any thoughts on the matter---also I am still having the flooding at 2/3's throttle and beyond which appears to be responsible for the inability of the engine to reach speeds greater thatn about 1700 RPM's.

Thanks,

Bruce

[Marian Claire]

If you have an air leak at the upper end of the carb. That could cause less suction in the carb. The carb can not draw the gas up to the intake. That could lead to a lean condition in the cylinders, loss of power above 1700 RPMs. The fuel then may pool in the carb. The idle adjustment, not the jet, would change the position of the throttle shaft. The age, 1969, of your A4 reminded me of my last adventure with my 1965. You asked for any thoughts. Dan S/V Marian Claire

[Bruce A]

Hi Dan,

Thanks for the input. I guess it may be time to get out the vacuum gauge and see if I can see anything that points to an air leak. I was also thinking that maybe a loss of vacuum during the intake stroke (due to problems with rings or valves at higher RPM) may cause this kind of a problem.

Bruce

[MikeB.330]

It sounds to me like you float valve is leaking. Without a working float valve your fuel pump will just overfill the fuel bowl causing fuel to push up into the throat. Or your float level may be too high. Either one of those would exlpain both the power loss issue. See that's the pisser, too rich or too lean can = power loss.

Either way, pull the carb and go through it with a fine tooth comb.

Mike

[julian hood]

Hears my 2 cents worth , no charge. Had the same anemic power issues this spring. Finaly got a buddy in the cockpit and went below and adjusted the timing while we were out cruising. Walla! Power increased to 6.3 at 1700 and up to 7.5 at higher RPM's. I have the 3 blade Indigo prop and really like it. Hope this helps.

Julian Hood
Oday 27