150hp oil xfer probs

[Gulfsurfer]

1998 Cobia, new to me so I don't have any histrory except I've been thru the fuel system (all new fuel lines, racor filters, etc.) and cleaned up 9 yrs of Saturday boat maintenance and half !@#ed electrical repairs.

Dual Yamaha 150s, L150TXRW (port) & S150TXRW (stbd).

Stbd engine has the probs: oil won't xfer from remote to engine tank, even w/ the bypass switch. Tach for same engine not indicating rpms. LCD on, reading 0 rpms. checked green wire behind tach, it's connected. Seem to think this may be related to lack of oil xfer because of yr of engines (newer than 1995).

OK, I've searched and read the threads, read the Bass & Walleye article, done the prelim troubleshooting and am asking for help. Actually if I had a wiring diagram (rigging guide etc.) I could probably find the problem much easier.

Sourcing the pump at engine connector w/ 12V, pump runs.

Tested the harness between the engine and remote tank plug, harness rings out good.

Cleaned remote tank, tested switch at remote tank: pull switch out, simulate low level, and yellow indicator indicates, just like it should.

Haven't done anything w/ the engine oil tank switch beyondftaking it out and verifying the float is free. Feel like the bypass switch should do just that, bypass everything except the engine oil tank. Oh, I checked the bypass switch, it's changing state from NO to closed when toggled.

Does anyone have any info on tach wiring so I can elimate that from the equation? or any other suggestions.

thanks,
RM

 

[rodbolt]

Re: 150hp oil xfer probs

tach has nothing to do with oil transfer, toss it in the creek and the oil system can still work.
you have a wireing issue.
at the remote tank, make sure the brown pump wire has 12v anytime the key is on, especially when the circuit is loaded.
the blue wire is for the transfer pump ground, two ways to ground it. either the control module in the ECU or by manually toggling the transfer switch.
there is a splice in the 10 pin main harness just aft of the engine connector that can fail. thats why you need to test for 12V while the circuit is loaded.
the black wire at the remote is the ground path for the low remote level indicate. its about the only time an open circuit cndition lights a lamp on yamaha products.
once the switch opens or the tach sees an open circuit it lights the yellow lamp and prohibits automatic transfer however manual transfer can occur.
so see,go back, think logically.
My guess is a bad connection someplace.
that splice is where the brown 12v+ pump wire ties into the key on yellow.
hopefully not only did you drain the engine tank before you removed the switch and screen assy you also retrieved the filter to tank seal and replaced it. otherwise you may be posting about an oil pump failure due to debris or a lack of oil due to the seal being shoved down the oil intake tube and blocking the flow.
sometimes it just dont pay to shade tree things.

 

[Gulfsurfer]

Re: 150hp oil xfer probs

OK, I brought the malfunctioning tach into this problem since another thread stated that after 1995, the interlock for preventing overflow while tilted up was replaced w/ an ignition signal as the permissive to transfer.


I suppose to get the tach working I'll check the alternator/charging system. Isn't that where the tach gets its signal? I've checked the obvious connections behind the tach and at teh ignition switch module.

That's a good suggestion to check the brown wire under load. I'll do that as soon as I can.

thanks,
RM

 

[rodbolt]

Re: 150hp oil xfer probs

trace the wiring diagram carefully, you tell me where the tach signal ties to the charging system.
yes in 96 the systems on the V6 got standardized for the us market so that for NORMAL transfer the engine had to be running, 90-95 ran through the trim switch.
however tach signal has nothing to do with the manual switch, the manual switch simply takes the blue pump wire to ground allowing a circuit path reguardless of engine running or not. as long as the brown wire can maintain 12 volts.

 

[Gulfsurfer]

Re: 150hp oil xfer probs

OK, got to the splice aft of the 10 pin conn at engine. I measure 0 V at this connector, either side of it. I assume this yellow wire is the same one which turns warning buzzer on in key switch(?). The buzzer works.

If it is the same yellow, where could the key switch yellow be disconnected between the key switch and the engine connector?

 

[Gulfsurfer]

Re: 150hp oil xfer probs

further troubleshooting revealed break in yellow wire (under insulation!) 5" aways towards engine connector. this repair fixed tach also. thanks for the help.