Engine and prop info needed!

[marcusdesade]

Hi all,

I just bought my S2 9.2C in July and I am very happy with it, generally. I am trying to wring another knot or so of speed out of her when under power, however and I although I got most of the original manuals, there was no manual for the mechanical gear. She's a 1983, and powered by a Yanmar 2GM. I have no idea whether the engine's ever been opened up, its RPM seems governed to run at 2100, max. The engine plate says its rated at 15 HP at 3400 RPM, but there's no way this engine would ever hold together running at that speed, I'm sure. The prop looks like it could be original, and I didn't get any numbers off it.

I have been looking all over the 'Net to engine specs without luck. I would like to source a rebuilt 2GM, preferrably a 2GMF (freshwater cooled) to repower with.

I'd also like to hear from any folk who have upgraded their props and had good experience. I had some pretty pathetic performance on one trip where I averaged 3.5 kts. due to current (no wind, had to motor) and from what I can find out I should be getting about 4.5 at least.

Can anyone throw me some scraps of information?

Regards,
Marcus

[USCGRET1990]

ummmm...you might want to relax a bit...if you want a speed boat,
then go buy one...sailing is about chillin and relaxin..no speed required..
of course unless you're into racing such as Giuliette...and lets face it, you can"t afford that mess...

[rperret]

marcus,

try looking at yanmarhelp.com or marinedieseldirect.com.

there is something wrong with that motor if you are not able to get past 2100 rpm. but i assume you have done the usual and customary troubleshooting - compression test, fuel injector, timing, etc, etc.

btw - when you state you have manuals - which manual? owner or SERVICE manual (either yanmar or Clymer) I have a clymer and could look up some specs for you.

Rick

[bcates]

Marcus

I have an 83 S2 9.2 (since 86) and it is a great boat. The 2GM is a great engine. The "Sweet Spot" on this engine is 2700 prm. It will run there all day long on about 3/4 to 1 gph and push the boat along at 4.5 to 5.5 kts. I would guess I have put a 1000 hours on the engine and it's never hiccuped. THe key is regular oil changes and filter changes and do keep an eye on water in the fuel tank. Make sure you use good fuel and oil additives. I use BG products in both.

I am current looking at a new prop to see if I can get another kt or so - this is the one I am checking out. We'll see how it performs - see this site
sailcdi.com/ppmain.htm

Anything else, drop me a note...

Buck

[ericroline]

Cal 9.2 with 2GM20, 14Dx12P RH prop. Rpm will go to 3600 while underway , but will not go much over 2400 while at the dock in forward. The engine RPM and hull speed are at about 60% efficient, 40% prop slip, up to 3100 RPM which is max hull speed. More RPM does not equate to more hull speed.