Post Number: 1
|Posted on Friday, April 22, 2011 - 11:21 am: ||
Gentlemen,and ladies where appropriate, I am a new member and this is my first post. Let me congratulate you on a great web site. The wealth of knowledge contained here is amazing. I recently picked up a Graymarine Four-91 Sea Scout that I bought on ebay a couple of months ago. The plan is to probably use this engine in my 1917 Johnson launch that I expect to be working on soon. The price seemed right despite the fact that it was missing the starter and generator. I thought that I had those 2 items on hand. I had what I thought was a Six 103 (six cyl, 2 carb,Gray eng. #92367) for a brief period a few years ago. It was full of water when I got it. I took some parts off of it that I thought I might need and traded. A manual that I have lists the Six-103 and Four-91 as using the same starter and generator (MZ4045,GFA4802-2). This Four-91 is a much smaller engine than that six, so the parts don't fit.
Here are my questions. What year is my Four-91 (Model S-S, Eng #14031)? Can anyone tell me what part #s I need? Does anyone have the parts that I need for sale? Either usable or cores to re-build. I'M assuming that this is a Y91 block. If so, I understand that the internal parts are readily available. Has anyone had experience buying this type of part from Graymarineparts.com or Van Ness Engineering? Or other sources to recommend? If I'm going to replace the starter and generator, is it possible/practical to go to a 12 volt system? The water pump on this engine appears to be gear driven, rather than off of the generator. I've seen pictures of them both ways. Is the gear drive newer or older model? Would the gear driven pump possibly make it easier to convert to 12v? I've been starting my Four-75 off of 2 6V batteries in series for 25 years without any problems, but that requires carrying 2 batteries. Any opinions on 6v vs. 12v? This engine is painted blue. I can't find any evidence of green paint underneath. I've seen pictures of Sea Scouts painted both colors. Would green be appropriate? I like green better. Does anyone have a flame arrester for sale? (1 3/8 inch OD on carb. straight pattern, not more than 1 1/2" long, book lists it as Zenith C4657)
I guess that is what I need to know for now. Any info that anyone can give me will be helpful. This is probably pretty basic for most of you guys. I hope that you don't mind helping out a newbie. ( Bruce, do you still have that 2 cylinder Cady if I change my mind again?)
Post Number: 569
|Posted on Friday, April 22, 2011 - 04:18 pm: ||
Starting a 6V motor with two 6V batteries is a tried and true technique to get the engine to kick over smartly, while preserving the 6V other "stuff"
The experience of folks who tried to have their generators re-wound to produce 12V is dismal to say the least. I think it has something to do with the limitations of the armatures plus the state of competence ( or otherwise) of the guy doing the re-winding.
I'd keep the 6V system and keep doing what you've done before, mainly because it works reliably.
Post Number: 263
|Posted on Friday, April 22, 2011 - 09:40 pm: ||
Rick, E-mail me off the board at firstname.lastname@example.org
Post Number: 83
|Posted on Saturday, April 23, 2011 - 09:27 am: ||
According to the chart posted at http://www.finewoodboats.com/Gray.htm
your engine is a 1935. My books show a 1935 sea-Scout-91 taking a GAS-4111 Generator and a MAK-4011 starter. The starter was 1935-1937 91in only. The generator was used on seeveral motors 1935-1947