Captain Slow Posted March 19, 2008 Share Posted March 19, 2008 Hi,I've been looking at four stroke engines recently and whould like to know if it is worth paying the extra for the pumped version.In particular, I've been looking at the OS 91 engines.Does anyone have any experience with or comments on the pumped or non-pumped approach?Thanks / CS Quote Link to comment Share on other sites More sharing options...
YakMad Posted March 19, 2008 Share Posted March 19, 2008 CS, I have the non-pumped version which i would have to say power wise is only as good as my cheaper ASP .91 fs, sorry OS, but if you are looking for more power from this size four-stroke I would recommend the Saito 1.00 (which I also have) it will pull bigger props than the OS and it's cheaper and no messing with pumps. Quote Link to comment Share on other sites More sharing options...
Ultymate Posted March 19, 2008 Share Posted March 19, 2008 The only real advantage of having the pump is the ability to mount your tank on or near the models C/G, set against this is the weight and complexity of the pump, you don't get any extra grunt. As YakMad has said the new ASP 4 strokers are great value for money as are the Saitos, often the choice comes down to personal preferance and or brand loyalty, personally I would'nt go the pumped route Quote Link to comment Share on other sites More sharing options...
Captain Slow Posted March 20, 2008 Author Share Posted March 20, 2008 interesting - i thought it would offer the possibility of more reliable fuel delivery (ie lower the chances of dead stick/problems). Saito are on my list of engines to try so that may be something for me to think about. Thanks! Quote Link to comment Share on other sites More sharing options...
YakMad Posted March 20, 2008 Share Posted March 20, 2008 CS, Four-strokes only really suffer dead sticks during the running in phase, once I have run in the engine in I will change the plug and adjust the idle needle, usually set rich from the factory to assit in running in, after this, dead sticks should be very rare so long as there is still fuel in the tank. The real reason for pumps is as Ultymate says is to allow the tank to be mounted on the CG, they are more trouble than they are worth and you will use more fuel, ask any YS owner. Quote Link to comment Share on other sites More sharing options...
Captain Slow Posted March 22, 2008 Author Share Posted March 22, 2008 ok, thanks - non pumped it is then Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 31, 2008 Share Posted March 31, 2008 Have you thought about a YS fourstroke? really powerful and utterly reliable . They are about the same price as a OS .The downside is they do like high nitro fuel .E.D Quote Link to comment Share on other sites More sharing options...
Captain Slow Posted April 1, 2008 Author Share Posted April 1, 2008 No I hadn't. I've just ordered a 91FS Surpass 2. I'm hoping its as good as my OS 2 strokes have been.As a newbie I've only got experience with OS and TT so my purchasing decision was based on the makes I already knew (and my LHS stocked). I nearly went for the 81alpha but the 91 was cheaper and appears a tad more powerful on paper Quote Link to comment Share on other sites More sharing options...
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