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Old 10-30-2015, 08:56 AM   #50
Sortie
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City: Merritt Island,Fl
Vessel Name: Sue Marie
Vessel Model: Prarie 29
Join Date: May 2010
Posts: 259
I have the 4 108. The boat was sold in Jan. 1978,hull number 7. I bought her from the original owner in 2010. Have all the original paper work including manual's for both boat and engine. The 4 108 is described as a 4000rpm engine, but is qualified by the builder as being a 3600rpm engine. With the present (also original specs.) 2.9;1 gear, and 18x12 L H prop(3 blade) she will turn up to 3500, providing a 7.8 speed. However, she quickly starts to overheat. My mechanic tells me this is common for the 4 108 at that rpm. Needles to say, we don't do that.


PO told me that the boat when new, cruised at 7 at 2600, and did 8 at 2900/3000. He claimed the fuel consumption rose dramatically at that rpm. Not a surprise. If I needed a new engine I would consider the 4 236. However, I do not. Very content with my fuel economy and speed and she is very comfortable, noise and ride. Sounds lie a sewing machine. No problems, she runs well, she likes it, thus I like it.


John
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