Yanmar SB8 versus repower, versus more space and a larger outboard?

[SailingFan]

This is interesting. That is only, what, 140 F? That is pretty cool, really. I will check my epoxy and see what the temp range for it is. If it is in range (and I think it likely is) then making a pan is precisely what I will do. That fixes all sorts of potential problems, and gives an added bonus of not having to pull the engine.

Now if I can only tighten the bolts without breaking/crushing the epoxy flange... LOL!!

[Halifax Sailor]

the files won't fit , too large to send and i cant get tham to attach. send me your email and i will send. may take more than 1 email

[Tx J]

Originally Posted by SailingFan

This is interesting. That is only, what, 140 F? That is pretty cool, really. I will check my epoxy and see what the temp range for it is. If it is in range (and I think it likely is) then making a pan is precisely what I will do. That fixes all sorts of potential problems, and gives an added bonus of not having to pull the engine.

Now if I can only tighten the bolts without breaking/crushing the epoxy flange... LOL!!

Hi SailingFan,
Making a new epoxy pan as suggested by Cheechako would be easiest, if it would hold up. It might be possible to fabricate one out of steel or aluminum (or have a shop do it too. But finding a replacement, new or used, is a long shot.
IIRC, the SB 8&12's were primarily used in construction type equipment, so there could be some well-stocked parts dealers around, maybe even whole used engines, and parts, since that market sector is much larger than marine. Have you looked beyond the marine area?

If you do a refit with a used engine I'd suggest that you go with more HP too. Depending on your engine space available, that SB8 has a lot in common with the other small Yanmars of that vintage, the YSE/B/M 8&12HP series and the 1&2 QM & GM's.
Some of their parts are the same, although I think with the Yanmar part numbering scheme it can be hard to ascertain.

The YS series are a horizontal layout engine (like a VW Bug or Lycoming/etc a/c's), but Yan may have/did used many of the same parts for the more common vertical designs. The YS's only saved a few inches of overhead anyway.

Some of the bolt-on parts can even be sourced from almost anything.
Parts are parts, if they fit and work functionally (dealing with these ancient, largely unsupported beasts or even new stuff and systems).

Your FL location probably has the widest choice and best stocked Yanmar dealers, and many parts are common with the ag, tractor, and work-utility Yanmar engines. Yanmar uses a 'territorial' distribution scheme, very un-competitive (monopolistic), and dealers in other geographic areas aren't supposed to sell across boundaries.

I have some documentation (a lot) on Yanmars (and other stuff), been downloading 'stuff' for years.
I'll try to attach some here.
The "Yanmar illustrated parts quick reference" is dated 2007, from 'Wooden Boatshop, Vic, AU'. It covers some common parts for many Yanmar engines, and makes it easy to compare, prices are A$ and outdated I'm sure.
The Yanmar YSB12 parts listing is from a EU source, covers the 'renewable' type parts, but gives the Yan #'s.
The Yanmar YSM8-12 illust parts breakdown has good exploded views, Fig 1 shows an oil pan, but might be different than yours.
I have a bunch of other Yan docs too, just ask.

Dang, PITA, can't upload the two pdf's w/"illustrated" in title, too big for CF (just under 2MB each, limit is 595KB each).

[Cheechako]

Originally Posted by SailingFan

The question is then, will the epoxy hold up to the heat and vibration of being bolted against the engine block while it is running? I have the materials otherwise...

Yeah, that is the question. I wonder how hot an oil pan gets? They make waterlift mufflers out of glass/resin. But I never saw them get very hot at all. I tried to repair a Yanmar heat exchanger tank with JB Weld once in Trinidad and it lasted only about a half hour. OTOH, I repaired a triple sheave v belt pulley with JB that was aluminum and got quite hot and it lasted fine. Go figure.
Maybe the thing to do is to clean the old pan well and just coat it all over with resin/glass and creating a new flange on the corroded away part? Out of glass I would want that bolt flange maybe 3/8" thick.

[SailingFan]

TxJ, I agree that if I repower, the engine HP is going up. The 8's were supposedly ok for lake work, and light weather, and I suppose when the wind is howling, you would use the sails on this vessel more (SADR is something like 15, so it would seem that she would LIKE higher winds), but my issue is more with currents than winds. In no wind, there is only current and wakes of other transiting vessels in the channels, or transiting narrow areas of the ICW, that I am concerned about, and if no wind at all, perhaps, along the coast (damned unusual in Florida to have ZERO wind along the coast). Those are where the engine come in handy, and the OB has already proven itself reliable in those conditions, other than the wakes. It also is an 8 HP and has a rather large prop and "long" shaft, but getting the prop deeper in and making things more streamlined when motor-sailing would be nice. Getting the gasoline into smaller containers and reducing the volume of it on board would be nice too. Reducing the necessary expended potential throttle settings to achieve hull speed would be nice too, as it surely would help make the engine last longer if it was not at full throttle all the time and it would probably reduce the fuel useage as well.

All these reasons contribute to my desire to place something of higher HP onboard, and 12-16 inboard, or a 20 OB would fit the bill, I think, assuming a 20 would not be too heavy back there. It may be.

In any case, I am going to go hunting my epoxy statistics and see how warm it can get before having issues, because that may well be the solution. Alternatively, I think (and I am not positive) that there is a JB Weld that is made for high temperature environments, and if I recall, it goes to something like 400 degrees F, which is far above the operating temp of that engine block or the oil within it. If that works, this thing is a done deal for now, until another engine falls into my lap somehow.

[SailingFan]

OK, I found about four or five versions of hi temp epoxy out there without even digging out my own materials. They range from 400 degrees up to 1400 degrees F. If they stick, this should work (assuming that I can remove all oil from the pan, and I have just the trick for that, 50/50 Pine-Sol and water mix, plus about two hours for soaking time). That should fix this issue, if I can drill and machine a flat surface on the epoxy without it coming apart.

[Tx J]

SailingFan,
One possibility: a lot of outboards are grouped in a series with the same basic block, pistons, maybe head & valves, etc.
Their HP ratings are determined by carbeuration and other minor changes like exhaust; to suit marketing and price points more than tech reasons.
Get a manual for your outboard and see if it was the baby of a series, there may have been bigger HP's (10, 12, 15...) basically the same except for a few 'minor' parts. If so, maybe bump it up the easy way.

PS: Those small Yanmars are like this, the 8HP differ little from the 12HP (I think). If doing a rebuild it might be possible to uprate them. Would need a close parts and specs exam first.

[Wotname]

Originally Posted by Tx J

.......

PS: Those small Yanmars are like this, the 8HP differ little from the 12HP (I think). If doing a rebuild it might be possible to uprate them. Would need a close parts and specs exam first.

Hmm... I expect it isn't; pretty sure it isn't with the YSx-8 and YSx-12. I'm only going by recent memory, the diameter of the piston and crank journal are much larger on the 12Hp version. A larger liner and crank would not fit the crankcase etc.

However as you say, it maybe worth checking parts and specs for the S series.

[Cheechako]

15hp Outboard is more than enough. In flat water 5 is enough, but when the water is bumpy you cant use a lot of HP anyway as the outboard is dipping in and out of the water. Old school 15hp weigh the same as 10hp, same block.

[SailingFan]

Originally Posted by Cheechako

15hp Outboard is more than enough. In flat water 5 is enough, but when the water is bumpy you cant use a lot of HP anyway as the outboard is dipping in and out of the water. Old school 15hp weigh the same as 10hp, same block.

I was considering these things, and had not considered uprating the outboard. That is a danged good idea since I already have the hard part, the engine and prop! Not sure about the SB8 and an uprating. I don't know if there is a governor, or maybe some sort of means whereby a turbo could be added, or if I can reduce the drag on the engine somehow (remove the alternator?). Still, as I have not actually run the engine, it may be sufficient as it is, as the prop is even larger than that of the outboard, and perhaps I could even run both at the same time to gain more thrust as the outboard and the inboard are counter-rotating, I believe, and both rated at 8 HP. They are also not inline with one another, the outboard is a bit to port and inboard is centered inline with the keel.

I will have to kick some rocks and see if there are ways to increase output of the outboard I have, because that 8 hp outboard is a little anemic, though it got me to 5 KTs over water with full throttle and three inches of hull growth prior to Equinox' drydock haulout. Adding some more hp would really help. With the removal of all those sponges, that grass, and the barnacles, I imagine the same engine would get another half knot to maybe more, and hull speed on this vessel assuming the 22 foot waterline is someplace around 6 knots, or seven at best.

Agree also about the lifting/hobby-horse issue, the outboard motor cavitation is severe when there are waves and especially short period wakes with which to deal, and you have to drop the throttle or risk racing the engine when that happens to the OB. The inboard repair would fix that, and would allow me to have two motorized power sources, two fuel sources, etc., plus sails, which was what I originally had in mind before this oilpan issue arose.

Another thing about that outboard, it has a couple wires that the PO told me are for charging the battery. Currently, they are coiled up and zip tied to themselves. If I decided to install them to some sort of charging bus, do I need a fuse of some sort? Also, how do I ensure they don't overcharge the battery? They lead from (I assume) the outboard's magneto and give about 8 amps of charge from what I was told, and that may be a nice way to top off (in addition to my solar and 35 amp inboard's alternator) as I motor along now and then, I was thinking, especially with my pending conversion of everything to LED's and 12 v systems where possible.
Lots to consider here... I may be better off than I thought.

[Suijin]

If it's an older 2 stroke 8 hp, then there is a good chance it's a detuned 15 hp. Carbs are different and maybe the intake. I know a couple of folks who have done it and it's different for different brands. For some the cost of the parts makes it uneconomical.

If you go the epoxy pan route I would consider making the flange out of aluminum bar stock and encapsulating it in the lip of the pan, or at least where the bolts go. Would add some stiffness and allow you to tighten down with less risk of cracking.

JB Weld is nothing more than epoxy with metal powder in it, as far as I know. I assume as a result that it has different thermal properties than your regular epoxies, for better or worse I don't know.

Speaking of your pump idea, it is possible in theory. I know because I spent 6 hours with a roasting pan and a turkey baster cycling oil from the pan to the oil fill once...

[SailingFan]

Originally Posted by Suijin

If it's an older 2 stroke 8 hp, then there is a good chance it's a detuned 15 hp. Carbs are different and maybe the intake. I know a couple of folks who have done it and it's different for different brands. For some the cost of the parts makes it uneconomical.

If you go the epoxy pan route I would consider making the flange out of aluminum bar stock and encapsulating it in the lip of the pan, or at least where the bolts go. Would add some stiffness and allow you to tighten down with less risk of cracking.

JB Weld is nothing more than epoxy with metal powder in it, as far as I know. I assume as a result that it has different thermal properties than your regular epoxies, for better or worse I don't know.

Speaking of your pump idea, it is possible in theory. I know because I spent 6 hours with a roasting pan and a turkey baster cycling oil from the pan to the oil fill once...

Ha ha!! I can just imagine how fun THAT was! NOT!!

My brother in law tells me that there were two pipes that led into the pan, and that the pan itself seemed to be just a holding area. If that is the case, and if the oil that drained down the crankcase sides and fell into the pan was not under high pressure, simply bridging the gap so that oil did not escape via capillary action and placing oil hoses to those two pipes that route the oil to this pan reservoir would fix my problem. It would not be a perfect fix, but it would work and keep the oil out of the bilge.

Not sure yet how I would do that, but if I did, the flange issue is a minor one, and I could just thicken the flange all around the original pan, place some sort of metallic material over the part where the screw hole reinforcements are required, use rubber and metal washers under the boltheads, and voila, the pan is "remade" with original parts and only a section having to be strengthened enough to resist the deflection of bolting it down (er, up...).

The sealant would provide enough seal to ensure that no oil flowed out between the block and the pan, and all would be merry. However, that said, I don't know how much oil pressure exists within the pan itself, or if the oil pressure that is presented is measured after the pickup puts the oil into the crankcase itself, and therefore the pan only catches falling oil that is not under pressure once it falls into the pan.

Still, if the pan is not pressurized, this is going to be a cakewalk. If it is pressurized, not so much.

[Wotname]

Originally Posted by SailingFan

.....

Still, if the pan is not pressurized, this is going to be a cakewalk. If it is pressurized, not so much.

It is not pressurised

[SailingFan]

Well, if it is not pressurized, all I have to do is make sure it does not actually leak when oil splashes against the sealed surface, so even if I don't actually make a perfect seal, I don't have to have pan bolts holding the pan that tightly where the flanges have rotted away. Therefore, I should be able to fabricate an epoxy flange there, and drill through it, use rubber and steel washers for giving tension, and bolt the thing together enough to mash the rubberized gasketing paste evenly. Not so tough, really.

[Tx J]

Originally Posted by Wotname

Hmm... I expect it isn't; pretty sure it isn't with the YSx-8 and YSx-12. I'm only going by recent memory, the diameter of the piston and crank journal are much larger on the 12Hp version. A larger liner and crank would not fit the crankcase etc.

However as you say, it maybe worth checking parts and specs for the S series.

Yup,
I was allowing for that. Knew the bore was diff. I think the block, crank?, head, etc., is the same or close. On a rebuild, with replaceable sleeves, it looked like it might work (haven't done one though).
For a few dollars more for different parts, why not, if at all possible?
You're already dragging around the same weight and dimensions (those YS's are heavy suckers), more or less.
Yanmar uses many of the same ancillary components, like pumps, injectors, alts, starters, on other series too.