Years Yamaha made 25HP 3Cyl 2stroke Engines?

[wmk0002]

Anyone know what all years Yamaha made the 25hp 2stroke in 3 cylinders? I have located one for sale which claims to have a lower unit issue stating it will go into reverse but not go into forward. They list the model as a 1988 but it appears to really be a 1998 from what I can tell. I know theses are sought after motors by many in the duck hunting community as they are capable of being heavily modified. I personally want it for my 1648 flatbottom, but I feel that the price is good even if it does need some work (assuming compression checks out) since they are pretty hard to find and worse case it prob has a lot of valuable parts on it. I looked up some LU parts for a 1998 model and the fwd and reverse gears are $100 each and a clutch dog is just $48 new which seems incredibly low compared to those parts I've priced for other motors.

 

[wmk0002]

Somewhat of a nevermind to my original post. Seller sent me a pic of the model number which is 30ELG which does go back to a 1988 model. Under the hood it looks exactly like pics I found of a 1999 3 cyl 25hp though. Would a 1988 30hp and 1999 25hp 3 cyl look the same under the hood? I have no knowledge of the Yamaha model design history.

 

[turbotodd]

Yes the 30 and 25 were "mostly" the same (carbs, etc different). Out here, a lot of guys used to buy up 30's and 40's and put 25 hoods or just the decals on them so that they'd pass the restriction laws on public duck hunting areas. Nowadays those things (25 3 cylinder Yamaha's) are everywhere for sale--and severely overpriced--since the 25hp restriction was lifted, and they're putting 60, 70, 80+ hp motors on their duck boats (15 and 16' tiller steer). I'll never understand it.

They're good motors unless some hack job has tried to mod it and/or it's been run with no premix or oil in the tank.

 

[wmk0002]

Yes the 30 and 25 were "mostly" the same (carbs, etc different). Out here, a lot of guys used to buy up 30's and 40's and put 25 hoods or just the decals on them so that they'd pass the restriction laws on public duck hunting areas. Nowadays those things (25 3 cylinder Yamaha's) are everywhere for sale--and severely overpriced--since the 25hp restriction was lifted, and they're putting 60, 70, 80+ hp motors on their duck boats (15 and 16' tiller steer). I'll never understand it.

They're good motors unless some hack job has tried to mod it and/or it's been run with no premix or oil in the tank.

Thanks Todd. I'm not sure what this particular motor has seen. After talking with the seller yesterday he said he purchased the motor along with a new boat from a local Edge dealer here in Alabama. He was told that the motor was freshly rebuilt and had been "blown up". The cleanliness under the hood seems to go along with that. Was also told it has 40 hp carbs on it. Seller said dealer also rebuilt lower unit but according to him his first LU issue was caused due to them failing to add lube to it as after failure he checked for shavings and said it was bone dry. Seller and his dad tried to fix it and while doing so noticed it had been cracked and welded but said it looked like a good job. After they tried fixing it, it only worked for a short while before losing forward gear and he said the hell with it. I figure if the LU welding job was done ok and the LU casing is good I can work on it (never messed with a lower though but know how they function). Back to it being rebuilt and having 40hp carbs on it...kinda makes me think it may have been one that came from Arkansas and saw some serious modifications that possibly may have even led to failure.

Aside from the carbs what other things were done to mod these motors? Anything I can look for without having to turn a wrench? Seems like I have read common mods are shaved heads, ported exhaust tube, and lightened crankshaft/flywheel. I'd prefer it to be stock although the carb upgrade would be nice if it was done correctly. Any input on what good stock compression numbers are for these? If the head was shaved what kind of compression numbers may I expect?

 

[turbotodd]

stock compression is 110-120 on my gauge. Everyone's gauge is different, however. Long as all 3 holes are not 150+ or under about 90, it's ok. If high, head probably was cut and would require high octane racing fuel to keep it from holing a piston. There was a guy at the recent duck boat drags locally that had one running methanol. Sucker was fast too. 60+ mph in a 15' aluminum boat.

There ain't much you can't do with them. The exhaust tuner mod is usually done if the block is off for any reason; and that's the only way to know. You can open up the carb throttles and look down their throats for reed modifications, but you can only see the "inside". Factory reeds are off-white colored. Boyeson's are usually a carbon fiber material and IIRC a 2 piece design which is visible from inside.

Personally, I won't buy a modified motor UNLESS a customer is basically giving it to me, and even them I'm just going to flip it. Most of them are hurt at some point. The ones that aren't will be sooner or later and even then it seems like they're constantly fiddling with 'em. Spark plugs fouling. Timing adjustments. Carb swaps. Etc etc.

Check out hydrotec marine. If you call 'em, they can tell you real quick what to look for. They can also tell you how to make a TON of power out of one.

 

[wmk0002]

Thanks again Todd. I agree, I don't really want a modified motor because I dont want to waste time fiddling with adjustments to things like timing to ensure the motor is running right and will last. However, I'm willing to overlook an upgraded carb/intake swap if it was done right. I absolutely want to avoid one with shaved heads and lightened components though.

Right now they guy wants $1k for it. It has the messed up lower unit but it also comes with a Panther 55 tilt and trim setup. Also comes into play that its a long shaft and I need a short. I recently bought a Vance jackplate so I can make a long worth though. I figure I sell the trim unit and use those funds to buy/repair the lower. Lower unit parts are available and relatively cheap but I was told this lower was cracked and welded so I don't know if that is part of the problem. Seller claims it appears to have been a good job. He said whoever rebuilt the powerhead also did the lower but din't put any gear oil in it...when it first messed up on him he checked the oil and it was bone dry, no water either so he knows it was never filled. He fixed it himself and it worked for a while but failed again which pushed him to sell. He has one more lower unit job under his belt than me as I've never messed with them but they seem like something I can handle. Just a matter of having a good casing to start with and hopefully some salvageable internals.

So far though, no luck finding a 30hp lower online. I read elsewhere that the 40 and 50hp 3 cyl models will fit with minor modifications but haven't found any more details on what all that entails. I do know there are a ton of them available and for not too bad of prices so it would be nice if true.

All in all, I'm leaning towards taking a risk on it. I know demand for these are not as hot as they used to be but I have found that there is still a good market for parts so I do know I can always recoup at least a good chunk of my money selling just the 40hp carbs and the electric start components.

 

[Matt193]

Here's one for you. Maybe you could arrange shipping?

https://up.craigslist.org/bpo/d/houghton-outboard-boat-motor-30-hp/6929431003.html

 

[thedude]

If he is asking $1k, then he isn't tired enough of fooling with it. Bottom line is it's a 30 year old motor that doesn't work. You might end up with more money in it than you think.

Sent from my SM-G973U using Tapatalk

 

[wmk0002]

If he is asking $1k, then he isn't tired enough of fooling with it. Bottom line is it's a 30 year old motor that doesn't work. You might end up with more money in it than you think.

Sent from my SM-G973U using Tapatalk

Yeah it's a big risk. Still haven't checked it out in person though.

The used motor market around here is ridiculous too. So many of these old 70's to 90's model small to midsized motors that are just so high priced. The few decent deals that pop up are scooped within a couple hours of being listed by people who are either retired or unemployed lol.

 

[nccatfisher]

I wouldn't touch it for 1K with the info you have given.

 

[wmk0002]

I checked out the motor today. It was super clean, had 140 psi on all 3 cylinders, and the lower unit wasn't as bad as I had thought. The shifting problem is due to a broken shift shaft rod. He had pulled the rod out before I got there so in taking it out all the way along with the cam, it allowed the shift plunger (which moves the clutch dog) to slide all the way forward engaging forward gear which was a good sign. It ran great on muffs and plugs looked good, like timing and carbs were well tuned. Panther trim unit was a little slow but worked fine.

I feel pretty good about it. I know most on here probably share the opinions to stay away though lol.

 

[nccatfisher]

Could you tell by the bolts, gaskets etc if the top end had been gone into? Such as if the case had been halved or the head had been off? That would play a big part in my decision also.

 

[turbotodd]

The duck hunters around here would pay $2K for it, blown up.

Some of these guys are just, well, plumb dumb.

 

[nccatfisher]

I have seen some of the vids of their escapades. And yes, that is about the only way to put it.

 

[wmk0002]

To update, I did buy the motor. The working Panther 55 trim unit plus the Powertech SRA3 prop that were included helped in my decision. I'll make a thread on my attempt at fixing the LU in case I need some guidance and as it may help someone else out in the future. Now I'm going to hunt a factory service manual so I can do a little homework before digging in.