Getting ready to work on the 140

interalian

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????--The holes in the flywheel are 5/16-NF !!!

The flywheel was sitting a bit too high to see inside, but stepping inside the boat shows the holes have a fine thread indeed.

That said, the coarse bolts threaded smoothly and easily into the flywheel that was on the 140, which is a 581849 instead of 581850 like the BRP site shows. This picture shows two of the same bolt, the one in the flywheel is bottomed. Seems some prior mechanic-like person re-tapped to coarse. It's a journey...

 
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interalian

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Got the proper 5/16" UNF bolts and the flywheel on the 90hp came off with a satisfying 'POP', no need to even tap the puller bolt.

Now, why so many different part numbers for the flywheel? 581849 for the '79, 582442 for the '82. And are they truly interchangeable? BRP says 581850 for both years...

 

interalian

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Both blocks completely stripped now. The 90's pistons look perfect and the block still has the factory hone marks mostly visible. Piston rings are all intact. Crank and bearings all look perfect. I can't figure out why it was so down on power - maybe the rings were just badly worn? I might pop them off and measure end-gaps in the bores, just for fun.

Using crude measuring tools, the 140 block may not have been bored out on its last rebuild. I'll have to take it in for examination at a machine shop. It is far too worn to consider using the good pistons from the 90.



Piston number 1 from the 140 is a TRW. Casting marks 322969 plus 470-99 which might be a date code. No idea if this translates into a number that correlates with STD or OS size:



Now, a point to ponder: would it be more economical to take the good 90 block and port it to match the 140, swap the exhaust filler and make it the basis for the rebuild? Add the 140's heads and carbs as well. Or is a set of pistons plus re-bore on the 140 block the way to go? My earliest intent was just to strip the power parts from the 140 and put them on the 90, but then I found out about the porting. Hmmm...
 
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Faztbullet

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Going to cost some $$$ to port and cut 90hp block to make it a 140hp.(not a DIY project) If it was mine I would have machine shop bore that damaged cylinder to .030 and see how much damage it will cut out, a little damage wont hurt it.Your going to need to use the 90hp crank as the 140hp centermain journal is toast.
 

emdsapmgr

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Agree with Fast, you've got a scrap crank. The main block bearing race which cracked looks like it's damaged the running surface of the crank throw. It's pretty rough, now. Dull and not shiny.
 

interalian

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Going to cost some $$$ to port and cut 90hp block to make it a 140hp.(not a DIY project) If it was mine I would have machine shop bore that damaged cylinder to .030 and see how much damage it will cut out, a little damage wont hurt it.Your going to need to use the 90hp crank as the 140hp centermain journal is toast.

Probably true about the cost of porting work. Just noodling.

I'm thinking the non-damaged holes may be worn beyond a hone job since the factory hone marks are long gone and all the bores are scored, and that would force new pistons in all 4. If they're in spec for hone, would you say using the good pistons (with new rings) from the 90 plus one overbore would be an OK solution? I'm trying to keep the $$ as low as possible as we're down an income in our house at the moment. Looking at the ring strike in the one hole, could it perhaps be ground out, allowing use of the good pistons from the 90?

I agree the crank is toast. To fit the 90's crank in the 140 block, would you use the top bearing and housing from the 90 as well, or are they a specific fit to the cank case? I'm quite sure the 90 was in 10x better shape than the 140, barring rust.
 
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interalian

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Agree with Fast, you've got a scrap crank. The main block bearing race which cracked looks like it's damaged the running surface of the crank throw. It's pretty rough, now. Dull and not shiny.

Nobody makes a -size bearing for a crank that needs linishing? BRP site doesn't even show the middle bearing.
 

emdsapmgr

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Most all crank parts diagrams for the V4 show the split bearing on the parts diagrams. For instance: It is item 25 on the drawing for a crank assy on 87 V4 engine. p/n 352960. Not aware that they make a oversize brg for an undersize throw..
 

Faztbullet

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Not aware that they make a oversize brg for an undersize throw..
Nobody does on a 2stroke outboard...you can send crank off and have rewelded ,ground down and treated so can use stock bearing. If the cylinders are in the shape you posted a hone job aint going to do you any good. Have a shop mike the cylinders and if past .003 wear bore it and finish the repairs , no sense in half arseing it try to save a dollar.
 

interalian

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Thanks for all the tips, I really do appreciate it.

I need to get the 140 block to a machine shop for evaluation now. Finding a good one may take a while.

My plan:

-Use the 140 crank case assembly. Inspect and measure bores and have them bored out as appropriate. New pistons and rings of the correct oversize.

-Use the crank, rods and bearings from the 90, including the top bearing assembly and bottom retainer. New seals obviously.

-Use the intake and bypass covers from the 90 to permit re-use of the later recirc system (how does that actually work, and what was it designed to do - lower emissions? improved fuel economy?). The bypass covers appear to be the same shape and size internally.

-Use the ignition system and wiring from the 90 (think I lost a power pack due to heat after hours of trolling during the last run last season, so maybe new ones).

-Try fitting the priming injector system and remove the choke plates.

BTW, the last thing I want to do on this project is 'half arse' the internals. Any savings will be on the 'bow-ton' bits that are easily changed should they prove to be problems. I DO NOT want to go inside the crank case again, not that I'm not having a blast working on this thing.

And not that I'm trying to squeeze the last bit of power out of this thing, but I notice a lot of rough edges in the intake ports. Is there any point in knocking them smooth while it's in pieces?
 

racerone

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You must replace the dowel pin in the 140 block !----You should replace the check valve at the center bearing too.---A bit spendy for the valve but it should be replaced.
 

interalian

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You must replace the dowel pin in the 140 block !----You should replace the check valve at the center bearing too.---A bit spendy for the valve but it should be replaced.

Gotcha, thanks! Is there a similar oiler for the top bearing?
 

racerone

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?????-----Look for a passageway somewhere that might feed oil to the top of the motor.
 

interalian

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OK - haven't looked that close yet.

Is the recirc system worth trying to fit? Does what exactly?
 

Faztbullet

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I notice a lot of rough edges in the intake ports. Is there any point in knocking them smooth while it's in pieces?
Leave em alone as keeps fuel mixture turbulent..If your going to turn it some RPM then that's a different story..
 

interalian

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No, keeping it in the stock range. This is not a speed trials build, just a sport boat for tubing and skiing. I expect to turn a longer prop than the 17 I have been using though.
 

emdsapmgr

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The recirc system was developed about 1983 or so. It's a system of drain hoses which recover excess fuel/oil buildup behind the reed boxes and recirculate if for combustion. It requires the 4 brass one-way valves be functional. Best to just replace them (not cheap) along with new hoses. You may not notice much difference in the way it idles, but that was the intent of the design engineers. Possible it's design was to keep the engine from "loading up" after idling a long time. Personally, my engines don't idle much anyway-so I don't see much advantage to the system.
 

jimmbo

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The recirc system was developed in the late 60s or early 70s. The purpose was to reduce the amount of unburnt fuel being discharged into the water. Older engine designs used to purge puddled fuel in the crankcase to reduce loading up. A benefit of the recirculation system, it improves lubrication of the upper crankshaft bearing
 
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interalian

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That's worth knowing. We like lake-trolling too, and don't have a kicker, so it may be an advantage to have recirc working. I'll pull the valves and test them first - the BRP site has them at $41 each, not cheap.

Since the intended purpose is to pull accumulated mix from the intake, I'm assuming the valve operates to permit draw from the bypass cover side during the intake stroke when piston draw exceeds crankcase pressure, and then closes under crankcase pressure.
 
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