Awakening an 83 BF100....

[flatheadlakemonster]

Hi all!

I was just given another OB motor. It seems as if when people find out you might be "into" them, they just appear on your doorstep. The latest is an 83 BF100 9.9hp. It seems to be in very good shape externally. all I know is that it wouldn't run for some reason, and "water contamination" was supposed to be the culprit. So far all I have done with the motor is remove the valve cover and I found some wierd stuff. This is what it looks like. Can anyone tell me why it looks like this? Also there was no engine oil in the powerhead when I got it, I have not checked the lower unit yet. This is the only thing I can find that seems to be wrong with it. The darn thing looks almost new!! Nothing is worn, all of the plug wires and rubber hoses are perfect!

Close up.

Like I said, I have not checked the lower unit yet, as this is where I would think the "water contamination" would be, but who knows.

Anyway, this is what it looks like. Not bad for free! Also cam with original owners manual(purchased new4/2/83), and the original fuel tank complete with tool kit, spark plug and oil can! I also got an engine stand(shown) and a 55 gal drum that has been modified to run motors in it. What a score!!

 

[hondon]

Re: Awakening an 83 BF100....

That is not contamintion from the gearcase.That is contamination from the engine oil or condensation after such a long lay up.Do a commpression test .If in doing so ,you feel things are not pulling over well ,stop.It should pull over easy with the plugs out.Check the condition of that oil in the pan.Drain it and see how much water comes out first.Keep in mind that these are tough little engines and have seen them bounce back from worse.Not pretty but good luck and keep us posted.

 

[Mas]

Re: Awakening an 83 BF100....

Did the motor go "deep six?"

MAS

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

As far as I know, the motor has never been swimming, haha! There is no oil in the gear case, and looking down the filler tube with my little fiber optic light, there is no sign of that same gunk in the lower case. But, I am also looking at a very limited area. I have not comp. tested it yet, but it turns over freely and feels like it will have good compression. On a 4 stroker, what should I be hoping for with the comp values? I have not drained the lower unit yet, but I will soon. I was planning on poking around with it last nite, but the weather was just too nice, the steaks too good, and the beer was perfect. Oh well!

 

[Mas]

Re: Awakening an 83 BF100....

Factory new compression is 151 psi. Yours will be lower most likely.

MAS

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

Thanks for the number! I know with the 2 strokes, they don't publish comp values, so I was wondering......

 

[Nick on the Bad Habit]

Re: Awakening an 83 BF100....

The only thing that I can think of, is that the t-stat is stuck in the open position and the motor never got to the correct operating temperature. That can cause condensation in the crankcase causing the crud to be left behind as pictured.
I would check out the t stat, and pull the rocckers for a good cleaning. I then pull the lower end to replace the impellor before starting so that no broken particles get caught in the water jacket.
Good luck!
Nick

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

thanks Nick!

I have yet to really get into this one I have been busy with other things. I am planning on going through the lower unit, as well as the usual service items, t-stat included. Do you think that if someone accidentaly put gear lube in it instead of oil it would do that? the guy that I got it from said that the oil was really thick when he drained it, and that made me think of gear lube for some reason. Maybe it just had thick oil in it for some reason or another. I will post up when I make some headway. Probably is not going to happen this weekend, as I have a new keg in the fridge that I am planning on getting in a fight with. In the end, I bet everyone loses that battle.....

Also, you mentioned the rockers, but I think I can clean them with out pulling them, but how about the valves, guides, and seals? Are they pretty resilient to corrosion and contamination? I would really like to get away without pulling the valvetrain.....hopefully......

Also, I thought that the valve train and such would be lubricated by oil, and not water. Would a stuck t-stat have to do with that? The oil and water systems should be separate. hmmm....

 

[hondon]

Re: Awakening an 83 BF100....

Yes that valve train is lubed by oil as is the rest of the powerhead.Cooling water and oil should at no time mix in this equation.

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

yeah, that is what I thought. I drained the lower unit lube and it looks pretty good, but that is as far as i have gotten so far. It was just too nice this weekend, and I bought new shotgun, so we had to go and shoot that, ya know?

 

[hondon]

Re: Awakening an 83 BF100....

ONCE AGAIN,forget about the lower unit or gearcase at this time.The motoroil pan is entirely independant of that gearcase.You have a MOTOR OIL leak that usually happens at the o ring type seal at the motor oil filler neck and can be hard to track down.Stop concentrating on your gearcase.

 

[Nick on the Bad Habit]

Re: Awakening an 83 BF100....

If the motor is run for a period of time and the t=stat is non closing, the motor can develop water condensation in the crankcase. If allowed to remain inside the crankcase during storage the water can start rust to occur.
Nick

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

Thanks for the help guys, I finally got both my other motors sold, so this one it going to be next up. I hope to maybe start taking it apart this weekend to see what I can see....I'll keep you posted!

Hondon, if you are still reading this I realise that I am not expressing myself correctly. I have posted up "gear case" in many cases where I actually meant "crank case" Sorry for the confusion!

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

If anyone is still watching this thread....I got it fired up today. Finally got the engine fuel fitting figured out, and a fuel hose made. It took a bit of coaxing, but she ran.....and then I had a nice emulsified oil leak around the oil filler housing. I am now looking for a gasket/oring kit for this motor.....anyone got any leads? I would really like to get this running soon. Also once, I get the leak fixed, how do I go about getting all the bad oil out of the motor? I drained the crankcase oil, and it was nasty, oil, water, and Seafoam. I figure that once it is sealed, I just have to run it a bit, and then change the oil, run it, and change the oil, and so on. Is there anything I should be addding to oil to clean it out in this case?

 

[speedyspencer]

Re: Awakening an 83 BF100....

Flathead.. I have the exact same motor basically though it's an '86 and its a 7.5 but it looks the exact same! Your's is mint though mine is getting a bit rough on the outside..Your oil leak around the oil filler body could be a very lengthy fix if the oring is gone on the inside of the filler body. Mine went after i ran it for a while with the impeller not working correctly and it burnt out the oring. There is a hose on the bottom left of that oil filler body that pulls water up from the impeller and before it goes to the tstat it runs through that filler body and if the impeller wasn't pulling up enough water then it can burn out that oring inside there and it will start to leak in the oilpan. This is not good!!! Actually, to be 100% correct you would have to replace the filler body as a whole since it is actually plastic and it will warp and won't create a good enough seal on the block anymore. This is what i had to do and it's a better fit anyways. You can order a new oil filler body from your local Honda dealership and the new piece will be aluminum like the original block and same colour so it looks much better also! Although it is a process to do this fix yourself. You must drop the lower unit, drop the midsection then go up through the bottom and remove hidden bolt holding the block down and then lift the block up slightly and turn it to the left as you cannot remove the four bolts on the filler body without doing so. I know sounds complicated but it works. Look into it and yes you should just be able to drain the oil a couple times and this should remove the contamination in the pan. Run it on your stand once you have it working and let it warm up with new oil then drain it while its warm..the oil will drain better.

Are you selling this engine?? I'd really like to know, it owuld be a cool mach to my BF75 I see you are in Minnesota so it wouldnt be too hard to meet as I'm in Ontario, Canada. Lemme know and good luck!

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

Spencer,

Eventually I will be selling this motor. I haave come to the conclusion that with a new baby, and a new house that I won't have time to get my boat the way I want it, so I think I am going to sell it, and the last motor. I won't sell it until it is running like new again, though! And this baby is almost new!

Also, I live in Montana, not Minnesota, so it may be a longer haul than you would think!

I started looking into it, and came to the same conclusion that you did about the leak, I also had water squirting out of the oil filler flange, which would lead me to believe it was warped also. One of the bolts was loose, but even after tightening it, it still leaked, internally and externally. I will talk to my honda parts guy here in town and see what I can come up with. Now all I need it enough time to get this thing apart, fixed, adn back together!

 

[speedyspencer]

Re: Awakening an 83 BF100....

Montana eh, lol, a little bit further that i thought. I guess i don't know my state abbreviations all that well but im sure it could still be shipped if you ever want to sell it. Let me be the first to know!!

And good luck with the repairs, I know it took me a couple days to fully figure it out but i ordered a service manual and it helped loads. Once it's ready I'm sure it'll rip like all Honda's do. Have fun and thanks!

 

[flatheadlakemonster]

Re: Awakening an 83 BF100....

Well that is OK, I bet the only provinces I can think of are BC and Alberta!!

Luckily the motor came with a service manual, and I think I found the parts, so I am going to get them ordered, and have at it! Now the wife may have me talked into keeping the little devil for a bit, but I would rather sell it and buy something bigger(the lake we use needs power!!)

Anyway, I will keep this updated....I just ordered the replacement parts today, so I will get the lower and mid units off, and hopefully have it ready for when the parts get here. My new goal is to have it running by labor day for the weekend, and then we'll see how it all goes.......