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Oil light on a BF100

D

deltarat

New member
"Hello all I'm new here an

"Hello all I'm new here and I hope that you can help, I can't seem to find any information on the problem that I'm experiencing, and I have serious issues with paying a "honda" mechanic $110.00 an hour to look at my problem and go "duh, never seen that happen". Which is pretty much the response from the two shop's that I have called so far.
Ok here goes. On Saturday I purchased a Mid 80's (red white and blue cowling) BF100, it has the cdi unit and horizontal carb. The unit has been sitting for a year or two, hooked it up to the back of my sailboat, fired on the 3rd pull and idled and ran fine. I took the gas tank down, filled it up with fresh gas and stp gas treatment (not the whole bottle) later that afternoon we took the boat out to watch the sunset. The engine powered us out of the marina (about 15 minutes at 1/2 to 3/4 throttle, and half way across the river then I noticed the green oil light flicker then go out, before I could reach the motor and throttle it down. I was not able to get the engine restarted and we ended up being towed back in. The next day when I took the cowling off I discovered that the small rubber hose coming off of the head, for the water discharge was cracked and had filled the lower part of the engine case? with water, I pulled the motor off of the transom, turned it on it's side and drained it, then I was able to get the engine to start and idle by feathering the choke but no oil light.
I took the motor off of the boat, brought it home, took the oil pressure sending unit off (btw I did check the oil level it was good) and cleaned it, then put it back in. When I started the engine the green light came on at idle then when the engine was rev'd the light flickers and goes out, then the engine dies. I have pulled the wire to the sending unit off and grounded it to the block with the same results so I do not believe that this is anything to do with the actual oil pressure or sending unit.

My questions are has anyone ever seen this? If so how do you fix it? If not I have tried to test the green light, thinking that the water may have caused part of the problem, but it does not light up with 12v, how is the green light activated? Is it some kind of pulsing current? If so how do I test for that.

Thanks in advance for any help you can give."
 
so did you check the oil press

so did you check the oil pressure with a gauge?

if that light goes out the motor goes into reduction mode

sounds like you have an oil pump problem
 
"If the oil pressure is OK wit

"If the oil pressure is OK with a real gauge, then you have an electrical problem in the indicator circuit."
 
"I will probably be able to te

"I will probably be able to test the oil pressure with a guage this weekend. But as I said I ran the engine with the oil sensor lead disconnected and grounded to the engine, with no change in the problem. So I suspect Robert is right, is the "indicator circuit" part of the cdi box? If so is the only way to fix that problem to replace that box?"
 
The lamp circuit is powered by

The lamp circuit is powered by the charging coil. The ground side of the lamp is in series with the oil switch and then grounded to the chassis.
Nick
 
"Ok here's an update, than

"Ok here's an update, thanks for all of the advice and info.

So far, the engine now runs The oil light still goes out at anything higher than 1/8th throttle, I believe it is a bad connection or when the engine was flooded with water (cowl down) something partially shorted? After a minute or so at 1/8th throttle or higher the water stream peters out and starts spitting water and steam so I believe that a water pump impeller is in order and since I'm in Northern California and there is very little wind on the delta this time of year I will probably take the next couple of months and go over the motor with a fine tooth comb, replacing the impeller, maybe pulling the power head and replacing the filter, the timing belt, pulling the carb and cleaning it thoroughly etc..
I'll keep you guys updated on what I find, I also found a parts motor for $150.00 that I will probably strip, clean, and categorize for future problems."
 
"I doubt that you have a pump

"I doubt that you have a pump impeller problem.
more likely a T'stat or crap in the intake manifold cooling passages. The amount of crap that I found there when I changed my T'stat was astonishing... Sometimes a thin wire snaked into the "block" at the fitting that the "water stream hose" attaches to works wonders. Of course, replacing the impeller on a used engine with an unknown repair history is a good idea anyway. Purchasing the Honda factory manual would be a good investment for you."
 
"Alright I know it's been

"Alright I know it's been a while since my last post, but with the holiday's and everything I really didn't have time to mess with the motor.

Here's where things stand right now.
I found a parts outboard long shaft BF100 for $150.00, and I got the guy I bought the original outboard from to give back a hundred off of the price I originally paid him. (I paid for a good running motor).

First I addressed the water flow problem, I pulled the lower end off of the parts motor for practice, and it turns out that it has a good impeller, housing and shaft. Then when I figured out how it all came apart with the help of a manual CD purchased from E-bay. I took apart the original motor and found the Impeller nice and supple, but the shaft was seriously grooved and the shaft hole in the housing was oblong or egg shaped, not what I would expect as a good thing.

I took the good parts from the parts motor, put them on the original lower end, put everything back together. Then I put a test gauge on the oil port and started the engine - 40 lbs of oil pressure at any rpm, and a steady stream of water out of the pee hole.
In the process I also found a broken wire on the rectifier. I changed out the oil pressure light with the parts motor, and sending unit. But now the light doesn't come on at all, I tried the original setup still no light. Well I know the oil pressure is good, and if I start to have any doubts I may mount an external oil pressure gauge on the top of the engine cover so that I can see the oil pressure at a glance, even connect the illumination circuit to the charging system on the engine so that I can see the gauge at night. We'll see a project for later this winter.
I ran the motor in my 50 gallon test tank for probably 30-45 minutes at differing rpm's in neutral and in gear, always had a steady stream of water from the pee hole, and the engine seemed to run great.

The next step is to take it out on the boat and see how it works, however as confident as I am that the motor is fixed I will still take my 2 stroke Evenrude with me as a backup!

Again thanks for all of the help, and I'm sure I will be back with more questions or tips of my own."
 
"Well spent some time on the b

"Well spent some time on the boat last week, the motor worked well, it did develop a problem where it seemed to be running out of gas, I checked the fuel supply - good
Pumped the primer bulb - good.
checked the fuel filter - empty?
I unscrewed the fuel bleed screw on the fuel pump and found that the tiny filter/screen there was clogged - I cleared that, and pumped the primer bulb a couple of times to clear the pump. I put everything back together and tried again - this time it worked so well that the fuel line at the carb started leaking. I pulled that line off cleaned the fitting re-assembled and tried again - success.
So far the engine runs well at all rpm's and holds a steady low rpm idle for cruising through the marina."
 
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