Start Yamaha f115 with no controls?

[scott06903]

Hi I found an '06 f115 for sale but the seller does not have a way to start the engine. I have a 1987 2 stroke 115 etlh and was wondering if the harness is compatible? I was thinking I may be able to pull the harness and use it to start the engine I am looking at. All I need to do is turn the engine over and test compression. Any suggestions?

Thanks

[boscoe99]

The 1987 harness should work.

In absence of a harness, find the ten pin connector at the front of the motor. Jumper the red wire terminal to the yellow wire terminal.

Then momentarily jumper the red wire terminal to the brown wire terminal. When the motor starts disconnect the jumper between the red wire and the brown wire terminals. Or find a way to apply battery power to the starter motor relay.

Presumes battery cables are connected to the motor.

[scott06903]

Thanks Boscoe, I'll search google images for the wire diagram and familiarize myself with it.

[fairdeal]

[/url]

[fairdeal]

hmmm

[scott06903]

Boscoe/group your thoughts please. This engine has not been run for 3 years, as such the fuel remaining in the VST has gone bad by now. I would kike to check the compression but I don't want to run the fuel pumps. Can I just momentarily jump red to brown to activate the starter but not the ignition? would this be the same as cranking with the kill switch not inserted? If this will work I think I'll set it up with a momentary switch.

Thanks

[fairdeal]

yes, the starter activation circuit is independent,
so applying power to the starter relay (red to brown) will crank,
but nothing else will be energized,
of course the engine will not start, there will be no ignition and no fuel pump

btw there is a drain in the bottom of the VST
(some models even have a handy drain hose already attached -
but I'd have to look up the '06 F115 to see)

with the drain open,
its easy to use the primer bulb to push as much clean fuel through as you like

[scott06903]

I made a simple jumper and it worked on the 87 115. If I want to kill the engine on a 4 stroke do I just jump white to ground? for the 2 stroke I just choked it to make it die.

the one I made is very simple but for a 1 off it works fine.

[fairdeal]

If I want to kill the engine on a 4 stroke do I just jump white to ground?

yes, that's it

[scott06903]

so I picked up the engine 2006 f115 that had been sitting for 3 yrs. Cosmetically its in great shape. I changed the oil emptied the vst and filled it 2x to clean out old fuel. I turned it over by hand then connected the red and yellow I heard the pump run then I connected the starter it struggled to turn over I thought it was a weak battery. I tried the starter again and after maybe 2 revolutions heard a loud gut wrenching snap.

I think I hydro locked the engine with fuel. When I changed the oil I did notice it was above the hash marks so higher than it should have been I also now think the extra volume was fuel. I pulled the plugs 4 3 2 were fine, when I got to cyl #1 oil came out when I removed the plug..

I guess this means the block is cracked and is a lost cause?
some advise would be appreciated.

[99yam40]

you will have to open it up to see what snapped, maybe that was just the starter making noise or breaking
with the plugs out does it turn over OK.
you should have done as you said and checked compression before buying it

I do not see how #1 would be full of oil when it is the top cylinder

[scott06903]

I just turned over the engine and oil comes out of 1 and 2. It turns over fine with the plugs out. I don't hear any grinding or crunching. Yes I should have compression tested it prior to buying no doubt.

[99yam40]

I just turned over the engine and oil comes out of 1 and 2. It turns over fine with the plugs out. I don't hear any grinding or crunching. Yes I should have compression tested it prior to buying no doubt.

Seeing that it turns over well with no plugs in, then I am not sure what was hurt.
maybe the injectors on 1 & 2 are stuck open and dumping gas into the cylinders

compression or leak down test now maybe?
bent rods?

[scott06903]

My thought as well, stuck open injector(S) I had one stuck open on one of my 225's it dumped a ton of fuel into the exhaust and the gph read at idle as if I were at 2500 rpm.

When you say open it up and see what broke are you suggesting top end or split the whole thing open?

thanks

[TownsendsFJR1300]

A compression test (with all plugs out) should give you some answers..

Question (not answered), the cylinders are numbered 1-4 FROM THE TOP DOWN... Is oil coming from 3 & 4?