Two Quick Questions

[RetroActv]

1. On a 92 Yamaha pro 50, how do you determine the adjustment on the screws that control the flow of the carbs? I have 3 cylinders and 3 screws, but not sure how many turns to bring them out from all the way in. I just cleaned the carbs a few weeks ago and ended up turning the screws out about 4 turns (it wouldn't run very far with them any further in than that), but is this out too far or not out enough? I don't have any guages on the boat..is there a simple way to figure this out? Sometimes going from idle to 3/4 or full throttle it will die a few times, but choking it or reving it up before engaging the prop seems to take care of that. I did put a new filter and fuel pump on about a month ago, so I can't imagine that is the problem. Could it be those screws?<br /><br />2. I ended up running my engine for 3 or 4 minutes I believe yesterday before I noticed the water pump stream had gotten clogged at the outlet. I'm not sure if my motor has an alarm for overheating, but how will I know if the damange has been done? I unclogged the stream nozzle and she idled and ran ok, but I'm more worried about the future..<br /><br />Thanks for your help!!

 

[ob]

Re: Two Quick Questions

retroactv, I believe you have an overheat alarm.Check for location of sensor and wires leading into powerhead near top of motor.Don't think you did any damage from your description. First question may not be as simple as there are several things that could give similar condition described.#1 don't know where initial mix screw setting was.Is the motor running clean at WOT?If so you've got idle mix adj. problem or carb sync problem.If not any number of things involving fuel delivery through carbs.Post back with reply to WOT operation.

 

[superman]

Re: Two Quick Questions

Hi Retro: I would suggest getting the correct manual for your engine and follow the procedure in it for your carbs. One can be found at the bottom of this page. As for your other question, If your are talking about the little peehole on the side of the engine that is a visual aid so you can see if water is circulating. If that was all that was stopped up and the water continued circulating then it shouldn't have done any damage.

 

[RetroActv]

Re: Two Quick Questions

Thanks for the quick replys! I borrowed the book from the library, but it didn't say much at all on how to adjust the screws. Or at least I couldn't really find out where that was written.<br /><br />I'm assuming by running clean at WOT, you mean no hesitation, or constant, good velocity? If that's the case, then it runs real well at Wot. And, in all honesty, there is no spot where it doesn't run well. It trolls down real nice, and it runs wot real nice. Sometimes after starting it or trying to go from say 1/4 throttle to 3/4 throttle, it'll bog down and I have to give it a choke or two to get it going. This occurs maybe 1/2 to 1/3 of the time. I thought it was maybe due to it being an older motor? I suppose 10 years isn't all that old, though..<br /><br />Thanks again for what help you can provide!

 

[ob]

Re: Two Quick Questions

Try to locate throttle linkage cam and roller and in nuetral see if roller is aligned on center with factory scribe mark.Another thing is remove intake box and assure at WOT position all carb flaps are equally horizontal.Close throttle slowly back to nuetral position and observe that each closes equally.If you have precission measuring tool such as hole guage you can open at several throttle positions and insure each flap is exactly equally open .There are adj. lock screws for each on linkage .If all checks well and you think you may have moved original setting slightly when servicing water check setting by opening each mix screw in 1/4 turn incriments until you get a response .Good or bad.Use this as baseline adj.The fact that it will settle out slightly when choke is bumped is one of two things,Carbs are out of sync or idle mixture is a bit lean.Also don't know your motor specifically but need to insure that the mix screw adj. is throttling air or fuel.