Oil Injection into intake manifold on outboards

[Chris1956]

My 1973 2 cycle 7 port loop charged motorcycle engine had very reliable oil injection. It consisted of a crankshaft-driven, variable stroke pump. The throttle setting controlled the pump stroke, and the engine speed controlled the pump speed. The oil was pumped into a banjo fitting on the intake manifold, where it mixed with the incoming gas and air. Did the Outboard manufacturers try a system like this, or was oil always mixed in the carb bowls? it would seem to me that the motorcycle system would react to changes in RPM or throttle setting faster than waiting for the mixture in the carb bowl to be altered.

 

[LubeDude]

Re: Oil Injection into intake manifold on outboards

If I am not mistaken, Yamaha and Suzuki are like this. Just seems I heard that.

 

[tommays]

Re: Oil Injection into intake manifold on outboards

i dont no how good it was because on the TM_400 suzuki motocross bikes from that time most people bailed on the pump and went to premix lost to many motors<br /><br />and everybody gave up on it on offroad bikes a nother thing to go worng on a hard working motor with a lot of dirt<br /><br />friends that were still riding 2 stroke street bikes around 1978 that had oil pumps in clubs had to ride in the back of the pack way to much smoke <br /><br />for what ever reason they never went past a 750cc 2 stroke and put everything into 4 stroke motors<br /><br />tommays<br /><br /><br />tommays

 

[rodbolt]

Re: Oil Injection into intake manifold on outboards

most all non EFI motors from suzuki,yamaha nissan and tohatsu worked that way. merc and jonnyrudes mixed it and sent the mix to the fuel bowl. thats why suzukis and yams are slightly more forgiving if you try to run with clogged carbs.<br /> it has worked well for many many years. I dont include customer neglect issues in relation to oil injection failures, same as bad water pump failures. those are customer neglect issues and will happen regardless. if I do not include customer neglect issues I have seen more dead enigines from improper premix than oil injection. you outta see the guys trying to premix 80-150 gallons at a time. danged hilarious.

 

[Chris1956]

Re: Oil Injection into intake manifold on outboards

Thanks for all the feedback. It was one of those things that bugged me that I didn't know.<br /><br />Ok I'll get a hobby!