Ok... I'm back with a post on this, and I'm happy to report... SUCCESS!
So, a recap for those of you following or perhaps someone in the future looking at this for the first time. First some baseline info:
Normally, my engines (both) sit for a week while we are gone. Upon starting, my procedure is 8 pumps of the throttle, key the ignition for about 5 seconds, then key off, pump the throttle 4 more times, throttle a about half, and turn the key again until they roar to life (usually around 2-4 seconds). For some more background, both engines rebuilt (one less than 100 hrs ago, and one less than about 50 hrs ago). My carburetor on the starboard side is an Edelbrock with electric chock (port will be changed out soon). Batteries on both sides have been replaced within the last year and a half. No other material changes to the engines or connected items for a number of years. Last season about midway through, things changed on my starboard engine:
SYMPTOMS:
* From a cold start - harder to start. Instead of 8 pumps, 4 pumps... it was 8 pumps, 4 pumps, maybe a few more... then start.
* Once started and running at about 1000 rpm for a few minutes as we prepped to leave, I'd knock it down to idle. No issues, but as time passed at idle it seemed to labor/hesitate a bit.
* After running for a bit (10-15 mins), putting it in gear or applying throttle would kill the engine.
* When the engine was warm, starting the engine was next to impossible. While cranking, the engine labored/hesitated as in the video above.
INITIAL THOUGHTS/DIAGNOSIS:
* Seemed like an electrical issue - changed batteries, checked grounds, tested the alternator output... all checked out.
* Was told by a fellow dock mate that maybe it was a sensor that was bad... LOL... No sir... not in 1967, LOL.
* Timing... checked the timing. It was set to 10 degrees (I was educated that it should be 8 degrees, so a small change), but 2 degrees wouldn't be a big issue.
* Moving on to more fun items... checked the flyweight movement on the distributor... they moved out, and back in as expected, no broken springs.
* Also swapped out my Mallory electronic ignition modules from port to starboard... issue did not follow, so the electronic ignition was good.
* There was also some input to check the gear on the bottom of the distributor, and that there could also be a secondary issue of a failing starter (labored starting).
ACTUAL PROBLEM & SOLUTION:
* After all of the diagnosis from above, there was now thought that the carburetor was the culprit, and something called "dripping secondaries" (For more info you can look for an artcile by Dick Morland in our archives - just search "dripping secondaries". I'll do my best to explain... Essentially, due to the angle of the engine, and some issues within the carburetor itself, the fuel leaks down to the last two cylinders of the engine as it's running. The engine can't burn it all, and over a period of time at a lower rpm, it sort of hydro locks those two cylinders, and they choak out. Trying to restart when warm, now causes the labored/hesitating start, but if the engine sits for the week (or overnight), the fuel evaporates to a degree (more the longer it sits), and thus the engine is able to start again.
* As I have the second carb awaiting installation on the port engine, It was a simple procedure to swap carbs - two wires,4 nuts, and the fuel line... about 15 minutes of my time. The first thing I noticed was that my gasket between the plate and the carb was "blown out" between 2 of the 4 barrels. Not sure how, or when this happened, but ok..I put a new gasket, and the second carb on... 8 pumps, 4 pumps, boom... off and running.
* I let the engine run for about 10-15 minutes... no change in performance (albeit a bit rich on the fuel - an adjustment I'll need to make. Keyed off the engine, then turned the key - no throttle...fired right off. Already an improvement without actually taking the boat out.
* We took the boat out twice after that... once for about a 15 - 20 minute shakedown, and another for about an hour and fifteen mintues. Both cruises were uneventful... the boat ran good, and no issues with lower RPM (do need to make some adjustments on the carb as mentioned above), and after getting into the slip, I keyed off the starboard, and fired it right back up... no issues.
* Now that I know, the carb will need to be tended to. Not something I'm sure I want to tackle myself, but it'll be the next step. The carbs came used to me from a fellow club member, but this one was fine for a small amount of hours over perhaps 5 or six years (remember that I am in the process of rehabbing our 42, so going out on the boat has been on the backburner), So once the offending carb is refurbed, I'll swap it out and have the other one gone through as well (or both over the winter). Come spring, we should be good to go on both carbs.
SPECIAL THANKS:
Without naming names, I'd like to thank a number of people that provided input, and direction in getting the diagnosis of this crazy problem. You don't know what you don't know, and I'm not an engine guy - but I'm learning. I appreciate the members of the this club, and others around me in our boating community in providing valuable information... as some of you know, finding people that know the "old stuff" is becoming more challenging. Thanks to all for the help, and hopefully this post (and Mr. Morland's article) will be helpful to others in the future.
Cheers!
C.
1967 42 Commander
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