More of this Feature • Part 1: Outboard Fuel Filter, Testing Compression, Cold-Weather Epoxy • Part 2: Intercooling, Stalling
Related Resources • Maintenance Q&A Index

How do I service the sight bowl fuel filter on my tender's 15-hp, two-stroke outboard? L.B., via e-mail
First place a small container under the filter to catch any residue. If the space is too tight, put a clean rag under the filter. Unscrew the sight bowl from the filter base, and discard the bowl seal. Remove the filter element from the bowl, and clean the element with solvent. If possible, dry with compressed air. If not, let the solvent evaporate in an open space and wipe clean when dry. An element that does not come clean after several solvent applications and wipings should be replaced. Install a new bowl seal--check your engine manual for the correct one--into the fuel bowl, and reinstall the filter into the bowl assembly on the filter base. Since the seal and filter elements are inexpensive items, you may want to keep a few spares in your toolbox. Before starting up your engine, test the installation by squeezing the primer bulb and checking for leaks. 

My boat has an older pair of inboard gasoline engines, and I suspect one of them is losing compression. How can I check this? D.E., via e-mail
Disconnect the ignition system by removing the high-voltage lead from the coil to the distributor. Remove all the spark plugs, and open the throttle all the way. Thread your compression tester into the first spark plug hole, crank the engine for a few seconds, and note the reading on the gauge. (The tester will hold the reading until you press the release button.) Do this for each cylinder.

Compare your results against your engine manufacturer's specifications, which will include an acceptable difference between individual cylinders. If two adjacent cylinders have similar low readings, the head gasket is probably leaking between them. If one cylinder has a low reading, squirt some oil into its spark plug hole and retest. If the subsequent reading increases by more than a few pounds, the piston rings are probably worn. If the reading doesn't change, the problem is probably worn valve guides. 

I have some fiberglass work to do over the winter layup. What are the inherent problems with using epoxy in cold conditions? S.D., via e-mail
The ambient temperature of the workspace is extremely important to the mixture's ability to cure and bond the right way. If the reaction is too slow, the epoxy may harden but never achieve the physical properties it was designed to reach. Moreover, the colder it gets, the thicker the epoxy becomes, reducing its ability to flow out. In addition it will be difficult to mix the resin and hardener correctly, as the material flowing through the dispensing pumps and out of the containers will tend to stick to those surfaces, preventing you from getting the proper mix ratio. The mixture will be harder to apply, as it will stick to tools and be far stiffer than at warmer temperatures. And finally, air bubbles may result during mixing and stay in suspension, creating problems in clear-finish applications.

If you have to do epoxy work during the cold-weather months, it is highly advisable to rent a space heater for your work area. In addition, follow the recommendations of your product's manufacturer for cold weather application.

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