Trey's Tech Corner
Trey’s Tech Corner
My Boat Won't Start!!
The dang boat won't start and that means one thing for a lot of us boaters---VAPOR LOCK. Vapor lock is a condition where the fuel in your fuel lines gets hot and converts to vapor. Electric fuel pumps don't pump vapor, so your engine will not run.
It accrues mostly when you have been out running, and you stop to pick up a skier or just anchor down to swim for a little while. After the engine is turned off, it will heat soak, and actually get hotter. When you go to restart it either won't start at all or starts and dies immediately. Depending on what engine you have and the type of fuel system is on it, determines who will experience this problem. Most of the marine engine manufactures have taken steps to eliminate this condition. Without naming names, I know of only one manufacturer that uses a fuel cell, and I've never seen vapor lock with them.
There are a few things you can do to avoid vapor lock:
When you come off of a plane, don't shut down the engine right away. Let the engine idle a couple minutes to let the temperature normalize. Then shut the engine off. Leave the blower on. This will draw in air to help reduce heat soak.
Always have fresh fuel. Old fuel, especially if bought during the winter months is more susceptible to vapor lock.
Make sure you change your fuel filters and seawater pump impellers regularly.
Installing a Bilge Pump
Bilge pump installation is straightforward, but it is essential not to overlook key details.
Mount the pump
You must not place the pump in the bilge unrestrained. If it falls over it will suck air and burn out. Pumps must be fastened down. Brackets are available that attach to a stringer or other vertical feature, or you can epoxy a couple of bolts to the bottom of the bilge to serve as mounting studs.
Float switches must also be fastened.
Use smooth-bore hose
Corrugated hose reduces pump output by as much as 30%, so always connect the pump to the discharge fitting with hose that has a smooth interior surface.Bends and long runs also reduce pump output, so make the hose run as straight and as short as possible. That may mean discharging the pump through the side of the hull rather than through the transom. However. . .
Place the discharge above the waterline
If the discharge is submerged when the pump runs, the ocean siphons back through the pump into the bilge when the pump shuts off. When enough water has entered to float the switch, the pump will eject it, only to have it siphon back again. This continues until the battery is depleted, then the water floods the boat until it reaches a level that gets the crew's attention.
The discharge fitting must never go below the waterline. If the fitting is through the transom, be sure it is high enough not to submerge when the stern squats. And if it is through the side of the hull, it must be high enough to remain above the water at the deepest angle of heel.
Use a thin-wall fitting
The through-hull fitting can further reduce pump capacity. To minimize this restriction, use a fitting with the largest possible opening.
Lead wiring up
It is essential to get the pump wiring out of the bilge as quickly as possible. Run the wires up and secure them so that they do not sag into the bilge water.
Don't skimp on wire size
A 3,500 gph pump will draw 15 amps, typically necessitating 10-gauge, or maybe even 8-gauge wire. Consult the ABYC Wire Size Table to determine the appropriate wire for your pump and length of wire run.
Use butt connectors and heat shrink
Crimp-on step-down butt connectors will assure a good mechanical and electrical connection between the supply wires and the pump leads. Enclose these connections in adhesive heat shrink tubing to make them water tight. You must slide the heat shrink over the wire and out of the way before you make the connections. Then center the tubing over the crimped connector and shrink it with a heat gun or by playing a flame beneath it. Be sure there are no explosive fumes in the bilge!
Connect to the battery
When you turn the power off to leave the boat unattended, you don't want to turn off the bilge pump. Connect an automatic bilge pump directly to the battery, not through the distribution panel.
Fuse the positive side
It is essential to have a fuse in the positive wire as close to the battery as possible. Some switch panels (see below) include a fuse. Otherwise join an in-line fuse holder to the battery end of the positive wire using a crimp butt connector.
Install terminal fittings
Do not strip the ends of the supply wires and loop them beneath the battery terminal wing nuts. Install crimp-on ring terminals the proper size to fit the threaded posts on your battery. Use a copper washer-not steel-between the wing nut and the ring terminal.
Three-way switch
If your bilge pump has a separate float switch, you may want to wire it to a three way switch that allows you to select automatic, on, or off. Be sure to support all wire runs at least every 18 inches using cable clamps or ties.
Two pumps
A bilge pump big enough to deal with a real emergency will do a poor job of keeping the bilge dry because the water in the discharge hose drains back into the bilge when the pump shuts off. And a big pump requires a big hose.
The ideal bilge pump arrangement is a small (400 gph) automatic bilge pump mounted in the sump to dispense with rain and shaft-gland leakage, combined with a high capacity pump (3,500 gph) mounted higher to deal with more serious ingress.
Stepping the discharge hose from the small pump down to 1/2-inch minimizes the backflow from the hose when the pump cycles, maintaining a dryer bilge. The large pump can be wired to a float switch if you prefer, but I think a manual switch makes more sense. An added advantage of this bilge pump configuration is that the high-capacity pump sits high and dry, extending its life indefinitely.
Checking Compression
If you suspect a problem with one of the cylinders ( a sudden loss of power or excessive black smoke), a mechanic should be summoned to do a compression test, preferably with an Engine Analyzer. This gadget uses a computer to give a more accurate compression readouts than can be had with conventional compression tests, which only indicate gross malfunctions.
Using probes hooked to spark plugs, the machine shorts out one cylinder at a time to measure the drops in RPM. The results are computed on a bar graph so that the mechanic can see exactly which cylinders are weak and which are strong. (A variation of 20% or more, either from the other cylinders or from OEM specifications, is significant.)
If the analyzer (or a conventional compression test) indicates a weak cylinder, a simple follow-up test by the mechanic will indicate whether rings are the problem or whether the engine has a less serious valve problem: Pour one tablespoon of oil (any more will hydraulic the cylinder and give a false reading ) in the cylinder and repeat the test. If the reading on the weak cylinder is equal to the reading on the strong cylinders, the problem is rings (ouch!). If the numbers continue to indicate a weak cylinder, valves are the problem.
Examining Hoses and Belts
Engine hoses should be checked to see that all are healthy. A Napa publication on belts and hoses reports that most engine hoses fail from the inside out as the result of an electrochemical reaction (called "electrochemical degradation" or ECD) that occurs as the hose ages and tiny cracks form in the rubber. These cracks then absorb coolant in the freshwater cooling system, which attacks and weakens the hose's reinforcement. (Mechanics report seeing the same condition on hoses in the raw-water portion of the cooling system, especially when the boat is used in saltwater.)
ECD can be detected by squeezing the thumb and a finger on the hose about 2" from the clamp. If the ends of the hose feel soft and mushy, the chances are good that it is breaking down internally and it should be replaced. The article recommends checking the middle of the hose, as well as the ends, to discover differences in softness. Gaps or channels that can be felt along the length of the hose also indicate impending failure.
A Few Suggestions:
Keep your engine (and bilge) clean. While this does little for the engine, per se, a clean engine will be easier to inspect and maintain which could give you an early indication of a potential problem. "Heavy" rust and scale on an engine should be sanded and painted. The exception is exhaust manifolds, which don't hold paint and are typically rusted.
Spend time reading your engine manual. Rather than rely on your aging memory, keep careful records of maintenance and repairs; you'll have an easier time keeping track of what has been done and when it was done.
Check the zinc at the heat exchanger (a relatively simple job). A zinc that is more than half eaten away should be replaced.
If you're buying a used boat: look for excess gasket residue and new paint, which is often found on rebuilt engines. If an engine was rebuilt, it's a good idea to find out who did the work and then check to see exactly what was (or wasn't) done. With some engines, problems tend to be ongoing and you don't want to buy someone else's headache.
If you have doubts, confirm the motor's serial and model numbers (and outdrive number, if applicable) and contact the manufacturer. This can usually be done with one or two phone calls. Manufacturers have motor, outdrive, and transmission information, including major repairs and recalls. Their records can often be used to ascertain the date of manufacture, shipping location, and original owner.
Engine Impellers
The impeller on a marine engines is a ware items & will need replaced regularly!
Most inboard engines impellers should be on a every other year schedule to change. This will keep engine cool & prevent boating down time.
Newer outboard engines impellers should be changed every 3 years. They are large vain impellers that last longer.
Generator impellers need replaced yearly. They are small vain impellers & will leave you with no AC.
Here's a generator impeller pulled out of a 41' Chris Craft Commander this past week. Notice all the blades are chewed off. NOT GOOD!!!!
Generator Operation
You should start & run your generator every time you come to your boat. Even if you not using it at that time. This will keep the fuel in the system fresh and keep the carburetor & fuel injectors from clogging. This will prevent rough running and no starting issues. Especially in these ethanol gasoline times.
Shawn Noble & I are very busy fixing you lake peep's boats. Make sure your boat is ready to go now by getting your preseason maintenance set for season. Get your maintenance work done now so your boat is ready and won't break down on you. I'm getting contacted everyday now on breakdowns. Mainly because you haven't done this service. Contact Shawn @ S & S Marine(see ad over at Services On The Lake) link to the left side side of the page to get your work scheduled today if your like me and don't want to get your hands dirty. I don't even have time to fix my own, LOL.
Chris Craft Commander Club - Styled in Fiberglass.