Frank Acampora
Supreme Mariner
- Joined
- Jan 19, 2007
- Messages
- 12,004
The question is frequently asked: "How much water should issue from the back two holes in my engine?" The definitive answer is: It depends!
Water comes up the water tube and passes through the block. If there is no bypass, ALL water exits from the rectangular hole in the back of the match plate (as shown in the second photo) and the smaller square connected by the channel. This water is dumped here in order to cool the exhaust downtube and also cool the midleg so that radiated heat will not burn a person accidentally touching the outer rear shroud. The channel helps to cool the matchplate in the exhaust area.
The midleg itself has a couple of drain holes as shown in the first photo. The exhaust downtube should have a gasket as shown in the last photo. This seals the downtube to the midleg
and allows water to drain only from the drain holes in the internal flange. NOW: depending upon the number of drain holes and whether or not some are plugged, or in the case of later Force engines, whether or not they have the plastic regulator tubes; some water will drain into the lower unit and exit with the exhaust while some will blow out through the bellows. The amount will vary with speed and design. However, the intent is to have the area around the exhaust tube filled with water and a solid stream issuing from the rear shroud holes at cruising speeds.
Water comes up the water tube and passes through the block. If there is no bypass, ALL water exits from the rectangular hole in the back of the match plate (as shown in the second photo) and the smaller square connected by the channel. This water is dumped here in order to cool the exhaust downtube and also cool the midleg so that radiated heat will not burn a person accidentally touching the outer rear shroud. The channel helps to cool the matchplate in the exhaust area.
The midleg itself has a couple of drain holes as shown in the first photo. The exhaust downtube should have a gasket as shown in the last photo. This seals the downtube to the midleg
and allows water to drain only from the drain holes in the internal flange. NOW: depending upon the number of drain holes and whether or not some are plugged, or in the case of later Force engines, whether or not they have the plastic regulator tubes; some water will drain into the lower unit and exit with the exhaust while some will blow out through the bellows. The amount will vary with speed and design. However, the intent is to have the area around the exhaust tube filled with water and a solid stream issuing from the rear shroud holes at cruising speeds.
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