F115 four stroke cranks, but won't fire

[Keyswayne]

Motor was running great. Went from one fishing spot to another, and then another, and then it just wouldn't fire. I thought it might be the "kill switch" and cut the white wire to that, still won't fire. No pinched hoses, fuel filter is clean, primer ball pumps up, 1/4 tank of gas, just recently had entire fuel system cleaned out and internal filter replace. Spark plugs recently replaced. Scratching my head.

[99yam40]

test for spark.
if you have spark then check rail fuel pressure

[pstephens46]

Is this motor new to you? Have you tried starting since this occurred? As in a day later or a couple hours later?

[Keyswayne]

No, had the motor new, has a little over 400 hrs on it. Just check Schrader (sp) valve, no pressure.

[pstephens46]

No, had the motor new, has a little over 400 hrs on it. Just check Schrader (sp) valve, no pressure.

Just to clarify, key has to be in the “on” position to check pressure.

[99yam40]

well, you need to find out if the lift pump is getting fuel into the VST , or at least pump the primer bulb to fill it and then see if the pump runs

[DennisG01]

I don't know the answer to this, but I'll ask anyways... when the kill switch is in the run position, is it "open" or "closed"? Meaning, if it's "closed" when in the run position (which for some reason, is what I thought it was?), then cutting the wire is the same thing as having the kill switch in the "off" position. Again, I'm not positive one way or the other, just asking!

[dark_star]

question, why cut the wire rather than unclipping the lanyard clip from the remote box ?

[fairdeal]

I don't know the answer to this, but I'll ask anyways... when the kill switch is in the run position, is it "open" or "closed"?

Yamaha uses "close to kill" -
specifically the white wire of the main 10-pin harness is grounded to stop the engine
either by the keyswitch or the kill switch, as they are in parallel

so "cutting a wire" could eliminate a defective (closed when it should be open) kill switch

[DennisG01]

Yamaha uses "close to kill" -
specifically the white wire of the main 10-pin harness is grounded to stop the engine
either by the keyswitch or the kill switch, as they are in parallel

so "cutting a wire" could eliminate a defective (closed when it should be open) kill switch

OK, thank you. Figured it was worth a shot - hoping for an easy answer for Keys!

[DennisG01]

question, why cut the wire rather than unclipping the lanyard clip from the remote box ?

He was eliminating the kill switch as a "variable" in this situation (on the off chance that the kill switch was faulty).

[TownsendsFJR1300]

Any updates?

[Keyswayne]

I took it to a marine mechanic. They called and said I needed a new VST pump, ...$1100. I had just had it in two months ago to a different mechanic, and they cleaned injectors, changed VST filter, scrubbed the fuel tank, and changed all the fuel filters, and primer bulb. There was some brown deposits in the fuel system. I"m trying to determine if something may have happened to the pump during this work? I have requested the new mechanic to write it up so I can call the first one and see what they say about lit. Seems like a heck of a coincidence.

[walleye1]

You can buy a oem pump here for 342.41 here on boats.net

[TownsendsFJR1300]

You can buy a oem pump here for 342.41 here on boats.net

Well, at $700 an hour, that's about right...