pilot screws ('93 225 HP 90 degree)

[Finley]

How critical is this setting? My manual says 1 1/8 turns out. My problem I believe was the adjust on the throttle sensor which I corrected to .5 vdc. But in checking, I found the pilot screws only out about 5/8 turn and all were out different amounts. None were adjusted out a full turn. <br />Enjoy this forum. Thanks

 

[rodbolt]

Re: pilot screws ('93 225 HP 90 degree)

hello<br /> the 1 1/8 is a starting point. it may run better or worse turned in or out slightly depending on your particular motor. its been my experience with yamaha that the book setting is very close. try it and see.a good digital tach is imperitive and the final adjustment needs to be done in the water.

 

[rodbolt]

Re: pilot screws ('93 225 HP 90 degree)

hello again<br /> a small footnote<br /> the pilot air screws on that carb do not adjust the air fuel ratio at an idle just how much of the air fuel mix goes past the needle. that is why the linkage adjustment on the carbs is critical. the air fuel mix is determined by the idle air jets and the idle fuel jets. both are rather tiny

 

[Finley]

Re: pilot screws ('93 225 HP 90 degree)

My original problem was, out of the hole, (full throttle)it completely bogged down. probably flooded. Are you saying not to set the idle by the onboard Tach? There are 6 of these pilot screws. Correct? Would you give me some detail as to how to adjust them? ie rpm I'm a bit confused based on your follow up.

 

[rodbolt]

Re: pilot screws ('93 225 HP 90 degree)

hello<br /> if you have the yamaha digital tach it only reads in increments of 100RPM most shop tachs will read in single digit increments.<br /> however<br /> start with the screws at 1 1/8 then move each one in or out in 1/8 incremnts while noting rpm. you will need to wait a min or two between each adjustment. if all else is correct the 1 1/8 usually works well. do the final adjustments with the boat in the water. if you have not checked the recirc check valves now would be a good time to check them as well<br /> do you have the service manual on setting the carb linkage ?

 

[Finley]

Re: pilot screws ('93 225 HP 90 degree)

What and where are these recirc valves? The carb linkage is correct but I'm unsure how to hook up my tach/dwell meter. It says positive to neg side of coil but I don't want to hook it up wrong. I have a Clymer manual but I can not find any info covering these check valves. Thanks so much for your help. This is an old 19'Grady that is my pride and joy. Love striper/Hybrid fishing.

 

[rodbolt]

Re: pilot screws ('93 225 HP 90 degree)

hello<br /> no worries<br /> its listed as a check valve assy. thgere are 6 of them<br /> follow the small gray tubes from the intake to the block. the little 90*fitting pressed in the block is a check valve. if they blow out it can cause idle problems and low speed plug fouling.<br /> use a small syringewith a piece of tubing and rubbing alcohol to try to blow and suck through them. fluid should only flow one way. if they are blown or clogged you can find it. if your brave you can use your mouth but odds are you will get a mouthful of gas nasties.<br /> the mouth method is NOT reccomended.<br /> dont worry most yamaha manuals fail to mention the valves either and not all yamaha V motors use them.

 

[Finley]

Re: pilot screws ('93 225 HP 90 degree)

Thanks. My last question. Where do I connect the positve lead of tach/dwell meter. My meter says positive to neg side of coil. <br />Thanks again. Great site.

 

[Finley]

Re: pilot screws ('93 225 HP 90 degree)

To Rodbolt.<br />Thanks for your help. Tried it out yesterday and she leaped out of the hole. Very responsive thru all throttle positions. I need to get an inductive tach. Mine will not work in this application.<br />Thanks again