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Re: Westerbeke 4-107 over heating issues

Name: Adam Wanczura
Category: General/Other
Date: 19 Mar 2004
Time: 05:20:59
Remote Name:
Remote User: awanczura


There are many factors which could give the results which you experience, from obvious ones like a rope around the prop to some of the items listed below. Prop size in relation to transmission output rpm: What prop size do you have? My 4-107 has a 12X8 prop behind the Paragon transmission without reduction. That is the recommended prop for this horsepower and rpm. Westerbeke recommends a 2" diameter exhaust for the engine, although 1 1/2" will probably suffice, since the engine cannot be loaded up fully with a prop which fits the rudder/keel aperture with the recommended clearance. To fully load the engine, the aperture would need to be enlarged to handle a prop of larger diameter. If you need more information on this, see "The Propellor Handbook" by David Gerr. I seldom run over 1800 rpm because this prop can't handle much more rpm in a displacement hull. Cooling water supply: A friend's boat recently solved his overheating problem by digging the zebra mussels out of the raw water inlet through-hull. Other things can lodge in the through-hull. If you can close the through-hull valve, remove the hose from the pump, add an extension to the hose, (the borrowed hose from another A37?) open the valve and push something (a smaller hose?) down through the valve, that should clear an obstruction, if there is one. Is there more water discharged with the exhaust after this? Is your thermostat operating properly or is it stuck? Put it on the stove in a pot of water with a thermometer, and heat the water until it opens. Don't tell your wife! Compare the opening temperature with the number stamped on the thermostat, and with the recommended in the Westerbeke manual. If the engine is not original, it may have previously been raw water cooled, so it may be scaled up. This is fixable. The heat exchange uses a pencil type zinc. These tend to corrode in half and leave a chunk inside the heat exchanger. When I bought my boat, there were half a dozen stubs rattling around in there. It took quite some shaking and jiggling to get them out. If the heat echanger has had leaky tubes repaired, the repair may consist of plugging off the offending tubes with solder, thus reducing the cooling capacity. Did you see any plugged tubes when you did your cleanout? That is a start. Maybe other Alberg owners have additional thoughts? Adam Wanczura

Last changed: July 25, 2016