Bob Maindelle Guide Lines Nov. 15

The damaged prop shaft seal, shown broken into two parts between the quarter and the intact seal, had green, 30-pound test monofilament fishing line embedded into it , which caused the seal to fail. Beware of fishing line in contact with your boat’s prop and/or prop shaft.

It was August of this year. The early morning white bass bite on Belton Lake was phenomenal, and my guide business calendar was packed full, thanks in part to the public school summer break being extended by COVID-19.

Fish were suspended above the thermocline and were easily targeted with downriggers. As I saw fish on side-imaging, I would mark them, then steer back to them, catching between one and six fish on each pass.

Then it happened.

On a turn which was a little too tight, I clipped the line of one of my two downrigger rods which was just a little too loose, thus creating a bow in the line between the rod’s tip and the downrigger release clip.

The 30-pound test monofilament got caught in the outboard motor’s propeller and began to quickly wind around it.

Of course, this is hard to miss when observed above the waterline, as line was peeling off that rod’s reel and the rod tip was jerking wildly. I have had this happen before and knew just what to do. I quickly put the motor in neutral to stop the prop from spinning, then turned off the motor, and trimmed the outboard up out of the water so I could physically grab hold of the fishing line.

I cut the line just down from the rod tip and, since the motor was in neutral, began pulling the line off the prop, which now spun in a counter-clockwise motion, opposite the direction in which the line was wound around it.

I got nearly all of the line off, but a short length managed to slip between the gear case and the prop. I knew that needed to be removed sooner than later, but that would have to be done off the water, besides, the fish were still biting big time.

That afternoon, back at my home base, I removed the cotter pin, the castle nut and the thrust washer, then slid the prop off of the splined shaft. There it was ... several more feet of the bright green mono wrapped around the prop shaft. I removed that, but also noticed there was a bit of mono caught in the seal which keeps water out of the gear case, and which keeps gear lube in the gear case.

I picked at that line with needle-nosed pliers, hemostats and then tweezers, but I could not get it all out. I had a few hours left until the motor would need to be serviced for the every-100-hour service. I hoped the seal would survive the assault by the mono and would check the lower unit fluid’s condition at that next service, which I would be performing myself.

I did that service recently. When I removed the gear case lube drain plug, then removed the vacuum plug just above it to start the flow of used lube into my drain pan, things were worse than anticipated.

The fluid was not the nice deep blue color it normally is, similar to the color of new gear lube. Nor was the fluid the color of caramel, like oil with some emulsified water in it will appear. No, what drained out was water with a few quarter-inch sized oil blobs floating on the top.

That monofilament had compromised the prop shaft seal, and water was easily entering my gear case.

Believe it or not, things could have been worse. As it was, my routine preventive maintenance caught this issue early enough that all that was called for was a new set of seals.

If allowed to go on uncorrected, a gear case failure could have resulted.

The retail price on a set of seals is about $20; the quart of replacement lube will run you another $8 or $10, and if you have a marine dealership do this for you, you will pay for about two hours of labor. Done thoroughly, a seal job like this should have a pressure test and vacuum test performed before the job is considered complete.

Why do I share this tale of woe with you? Because if you fish from a boat, eventually you will get fishing line wrapped around your prop. Whether it is yours, or a buddy’s or a kid’s or just stray line left in the water from someone’s snagged lure, this is going to happen to you eventually.

The trick is to respond quickly to keep a molehill from becoming a mountain. Do remove all visible line from the prop, and then go the extra mile to remove the prop from the shaft, even if you do not see any line from the exterior.

While you are at it and have the prop off, put a little marine-grade grease on the prop shaft splines to help keep your prop from seizing onto the shaft. Remove any line you find there and check to see if any line has had made its way into your seals. Use a flashlight to double check.

If line is in the seal, check the quality of your gear case lube. If it is a creamy white color or watery, water is getting into your gear lube and your seals need to be replaced.

This can be done in a fairly hassle-free manner by removing your gear case vent plug (not the drain plug), and using a piece of flexible wire as a makeshift dipstick to sample the gear lube fluid in the gear case. Wipe the wire on a white paper towel so the color of the lube you have sampled shows up well.

Remember, if the lube color is not approximately the same as new gear lube, you have issues.

I gave Josh Bingham, owner of Bingham Marine out on Farm-to-Market 439 near Belton Lake a call about this whole matter. He told me in an average year he will see around 100 prop shaft seals in need of replacement, and about six or seven destroyed gear cases where failed seals were not replaced soon enough.

The old saying, “An ounce of prevention is worth a pound of cure,” certainly holds true here.

Now, go check your prop! Trouble could be lurking in your garage.

(0) comments

Welcome to the discussion.

Keep it Clean. Please avoid obscene, vulgar, lewd, racist or sexually-oriented language.
PLEASE TURN OFF YOUR CAPS LOCK.
Don't Threaten. Threats of harming another person will not be tolerated.
Be Truthful. Don't knowingly lie about anyone or anything.
Be Nice. No racism, sexism or any sort of -ism that is degrading to another person.
Be Proactive. Use the 'Report' link on each comment to let us know of abusive posts.
Share with Us. We'd love to hear eyewitness accounts, the history behind an article.