The story of engine # 178848 so far...

[Baltimore Sailor]

If you've followed my saga this far, you'll know that I replaced the carb and spark plugs because of poor performance, which resulted in a smooth-running engine under no load that would rev up to 3000 rpm at the touch of the throttle, but give me no more than 900 rpm and 2 mph in gear.

Everyone I know told me that a boat that doesn't run between July and September in the Chesapeake Bay will have a ball of barnacles for a prop, so I motored -- very slowly -- over to another marina that hauled me out, scraped off the barnacles, and power washed the hull. When they put me back in she was clean as a whistle.

When I put the boat in gear, I still didn't get more than 900 rpm, but now I was doing 5.5 to 5.9 mph according to my GPS receiver. The engine also sounded rather like it was laboring, like a riding lawn mower hitting real tall grass. Still, it was dependable and never missed a stroke, even at those low rpm. If I idled down all the way while still in gear it would drop to 400 rpm and never even hint at stalling. Taking her out of gear would rise the rpm to 750.

So what's next? Points? They're probably as old as the old spark plugs, and I've been thinking of putting in the electronic ignition set. New plug wires? New dist cap and rotor? Could one or two of the new plugs be fouled already due to motoring over to the marina for haulout with the fouled prop?

Any and all advice is welcome. There's still a few things on the engine I haven't spent money on yet!

[David Masury]

The chance of having fouled plugs from a slow trip is pretty good... pull the plugs and take a look... I am willing to wager that they are pretty sooty.... you said that it ran well after having the bottom and prop cleaned of growth and that you had good speed, all this indicates that the general condition of the engine is good.... before you do much of anything I would just replace the spark plugs... while champions are good plugs, I feel that the Autolite 437 is a better plug for this engine....and is less likely to foul. If this solves the laboring issue then you are good to finish the season... I do recommend going to electroninc ignition, it just makes life easier.

David

[Don Moyer]

The part of your report that I find confusing is being able to move the boat to 5.9 knots with only 900 RPM available. Such performance would normally indicate a much too large prop. Do you know your prop size in diameter and pitch?

Don

[Baltimore Sailor]

I do now! It's a 10" 7.5-deg pitch 3-blade prop. It looks like original equipment, but I don't know the complete history of the boat. Does that sound too big?

I was thinking the same thing, performance-wise. I have no idea what size prop should be on the boat, but I was figuring "If I'm getting 5-6 mph at 900 rpm, I'll probably be able to ski behind the boat if I ever get up to 2000 rpm!"

I can also see how a too-big prop would pull engine rpms down from drag, right?

But as long as it's not hitting the bottom of the boat, will I be OK?

[msmith10]

The problem is that you'll be "lugging" the engine. Like your car being in 4th or 5th gear at 20MPH. Not good for the engine. "Lugging" is overworking, which leads to overheating. This can lead to predetonation ("pinging") which in itself is hard on the engine, and in extreme cases, piston slap, when abnormal expansion of combustion products due to predetonation causes distorted forces on the pistons.

[Baltimore Sailor]

The engine definitely is lugging. That's the sound I'm hearing that I described as "a lawnmower hitting tall grass".

Still, before all this hoo-ha started, I was getting 2000 rpm out of the engine with the same prop. So I don't think the prop is the problem, but some unknown engine factor I haven't worked out yet.

I still haven't done a compression test, which I will do when I replace/clean the new spark plugs I put in three weeks ago. I also haven't yet looked into the distributor to see what the points look like.

Regarding the timing, is there anything to be done besides warming up the engine, loosening the distrib bolt and rotating it to get the best rpm? No strobe lamp, no "deg. before TDC" like on my '70s-vintage Fords?

[baileyem]

Low RPM and Lugging

You haven't, by any chance , been messing with the stuffing box on the prop shaft and overtightened the packing nut ? That could cause your engine to lug.

[Don Moyer]

You've just added more complexity to the mystery. A 10 by 7.5 three-blade prop should not be too big for your boat. It is very close to the specifications of an Indigo Electronics prop which is a 10 by 7.2 pitch three-bladed prop. This size prop would be consistent with a max RPM of 2,500 RPM or so and a cruising RPM of approximately 2,200 RPM.

Don

[Baltimore Sailor]

You've just added more complexity to the mystery. A 10 by 7.5 three-blade prop should not be too big for your boat. It is very close to the specifications of an Indigo Electronics prop which is a 10 by 7.2 pitch three-bladed prop. This size prop would be consistent with a max RPM of 2,500 RPM or so and a cruising RPM of approximately 2,200 RPM.

Don

Amazingly, it is an Indigo prop. The writing on the prop says :

"Indigo 450
"10X7.4"

And it's a 3-blade prop.

You know, I had to evict a duck's nest out of my boat earlier in the season. She'd built her nest in one of the storage places in my cockpit:




Do you think I'm suffering from bad luck by kicking her out? That seems like the sort of bad luck from which a sailor would suffer.

[Don Moyer]

I've seen several examples in my life which would support the notion that kicking a mother duck off her nest would put someone at risk in terms of expecting any break from the Universal Powers that affect our individual fates.

Don

[Kelly]

Hear, hear!

I think the boat should have been towed to a wetlands site and left until the eggs had hatched and the family had moved away.

Watch out for karma!

On my boat, I have posted signs that clearly state, "No nesting allowed: please nest on neighboring boats".

Kelly

[Baltimore Sailor]

Now, I didn't know the gestation period of duck eggs at that time, but that gal was on that nest from before I bought the boat (middle of April) to when I had to move to another slip (the first of June). That's a minimum of six weeks, and Wikipedia says "The clutch is 8–13 eggs, which are incubated for 27–28 days to hatching"

So that would be four weeks, max. And I didn't actually kick her out, I moved the boat from A dock to E dock, with her along for the ride. She left and never came back, and when I checked the eggs they were all (of course) dead. I gave them a burial at sea. I shouldn't have said "evict," but I was concerned that moving the boat confused her and she couldn't find her way back again. I'd think ducks were smarter than that, but nests that change location probably aren't in her instincts, either.

I still wouldn't be surprised if karmaic justice of some kind was being dealt out, regardless.

[Don Moyer]

The burial at sea may have some bearing on your ultimate judgment, but I think you're wasting your time in pleading your case with your forum colleagues. It's highly unlikely that any of us have anything close to the clout it would take to intervene with the Karmaic Force to bring you more reliable service from your Atomic 4. We're all pleading our own deliverances from damnation after lifetimes of indiscretion.

Don

[msmith10]

I agree with Don. You've got much bigger problems than a little engine lugging. I do have to admit to evicting some barn swallows from my boom on several occassions, but I just have the feeling that swallows don't have the ephemeral connections that ducks do. Good luck.

[Baltimore Sailor]

How about points? Can bad points cause these problems?

(Cause if I need to sacrifice virgins, I don't know where to turn!)