Engine overheated , now lights stay on when ignition switched off

Started by wiggs, December 22, 2017, 09:39:30 PM

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wiggs

I came back from a 200 mile burn then got caught for 40 mins stationary / walking pace on my 87 fj in traffic in texas heat .I knew it was running hot so switched the motor off when I could, when I got home it was seriously overheating, opened the gas tank and gas almost bubbling. Switched off with key ignition , nothing ,  so had to use the kill switch. Engine shut down but headlight remained on . Thinking a relay / ignition barrel connector fused , shorted maybe with the heat - any ideas from members or similar occurrence
:Facepalm:
Current:
87 FJ1200
82 Honda CBX
82 Honda CX500 Turbo
82 Honda CX500 Eurosport
97 Honda vfr750
01 Honda RC-51

Pat Conlon

Crossing the Mojave my FJ has gotten so hot that the steel tank would scald my legs. I had to ride it like a bitch having a pelvic exam.

I never cooked an ignition switch but I can see it happening.  I can see the ignition coil cases cracking from heat. Tremendous heat build up under the tank.

Good news is that it sounds like your engine is still running. Check your valve clearances, then check the compression or better yet, do a leak down, make sure your valves and seats are not cooked.
Keep an eye out for oil smoke on start up, you may have cooked a valve stem seal or two or three...
FYI...RPM's Viton valve stem seals are superior to the oem seals: http://rpmracingca.com/proddetail.asp?prod=Head%3AVSS

Take the tank and fairing off...check everything for heat damage, wires, connectors, coils, fuel/vacuum lines, etc, etc.  

I've been known to slowly ride on the shoulder and split lanes, just to keep air flow moving across the engine.  I have no problem justifying it to a LEO.

Good luck, let us know what you find.  

Pat


1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

ribbert

The most common cause of a carburettor engine running on when switched off after severe overheating is dieselling. Worth checking by starting and stopping the engine again once it's cooled, before you embark on a complete dismantle and rebuild. The headlight would normally stay on if you turned it off at the kill switch.

Noel

Pat, I know that feeling of the tank being hot enough to melt the skin off the inside of your thighs, makes you wonder why they don't spontaneously combust.
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

wiggs

Quote from: Pat Conlon on December 22, 2017, 11:03:14 PM
Crossing the Mojave my FJ has gotten so hot that the steel tank would scald my legs. I had to ride it like a bitch having a pelvic exam.

I never cooked an ignition switch but I can see it happening.  I can see the ignition coil cases cracking from heat. Tremendous heat build up under the tank.

Good news is that it sounds like your engine is still running. Check your valve clearances, then check the compression or better yet, do a leak down, make sure your valves and seats are not cooked.
Keep an eye out for oil smoke on start up, you may have cooked a valve stem seal or two or three...
FYI...RPM's Viton valve stem seals are superior to the oem seals: http://rpmracingca.com/proddetail.asp?prod=Head%3AVSS

Take the tank and fairing off...check everything for heat damage, wires, connectors, coils, fuel/vacuum lines, etc, etc.  

I've been known to slowly ride on the shoulder and split lanes, just to keep air flow moving across the engine.  I have no problem justifying it to a LEO.

Good luck, let us know what you find.  

Pat

Thanks Pat, fortunately engine all good, valves , compression etc, I did notice my fuel cap not venting so removed the little flaps. Next job is removing the carbs and sending to rpm as I know I have idle jets blocked if balancing them does not help. Will then work on the mystery headlight , ignition switch and try tracing all wiring to see why It comes on as soon as I hook up the battery
Current:
87 FJ1200
82 Honda CBX
82 Honda CX500 Turbo
82 Honda CX500 Eurosport
97 Honda vfr750
01 Honda RC-51

wiggs

Quote from: ribbert on December 22, 2017, 11:56:01 PM
The most common cause of a carburettor engine running on when switched off after severe overheating is dieselling. Worth checking by starting and stopping the engine again once it's cooled, before you embark on a complete dismantle and rebuild. The headlight would normally stay on if you turned it off at the kill switch.

Noel

Pat, I know that feeling of the tank being hot enough to melt the skin off the inside of your thighs, makes you wonder why they don't spontaneously combust.


Thanks Noel, not actually engine run on , I just now have a defective ignition switch , it will not turn off the motor now so use the kill switch, but the headlight stays on so thinking wires or contacts fried somewhere?
Current:
87 FJ1200
82 Honda CBX
82 Honda CX500 Turbo
82 Honda CX500 Eurosport
97 Honda vfr750
01 Honda RC-51

Pat Conlon

Quote from: wiggs on December 23, 2017, 07:39:43 AM
.... so thinking wires or contacts fried somewhere?

Yep, you could try to disassemble and clean/repair your 30 year old switch or just spend $40 and get a new one

RPM has a couple of flavors, both plug and play with your '87:

Flat key:

http://rpmracingca.com/proddetail.asp?prod=M%2FC%3Aflatkeyswitch

Tube key:

http://rpmracingca.com/proddetail.asp?prod=M%2FC%3Aroundkeyswitch
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

Alf


wiggs

Quote from: Pat Conlon on December 23, 2017, 10:55:52 AM
Quote from: wiggs on December 23, 2017, 07:39:43 AM
.... so thinking wires or contacts fried somewhere?

Yep, you could try to disassemble and clean/repair your 30 year old switch or just spend $40 and get a new one

RPM has a couple of flavors, both plug and play with your '87:

Brilliant - thank you

Flat key:

http://rpmracingca.com/proddetail.asp?prod=M%2FC%3Aflatkeyswitch

Tube key:

http://rpmracingca.com/proddetail.asp?prod=M%2FC%3Aroundkeyswitch
Current:
87 FJ1200
82 Honda CBX
82 Honda CX500 Turbo
82 Honda CX500 Eurosport
97 Honda vfr750
01 Honda RC-51

Pat Conlon

I'm partial to the flat key switch. I like the dust shield, something that is missing on the tube key switch.

I've been meaning to take Randy's flat switch down to my locksmith and see if he can change the tumblers to match my tank and seat key.

It's on my list....
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3