1988 Yamaha 30hp long to short shaft conversion?

[scout-j-m]

I've mainly had OMC motors along with a few Mercuries but dont have any experience with Yamahas. I recently found a 1988 30hp Yamaha Model# 30ELG for sale which is listed as having shifting problems. Surprisingly, LU parts are pretty reasonable so it may be worth a buy.

My issue is that I need a short shaft motor for my boat. I have a jackplate so I could probably make a longshaft work but it would be nice to know if a shaft length conversion is possible. I pulled up parts for both this model as well as the 30ESG short shaft and began to compare parts. So far, Iv'e seen that the driveshaft, uppercasing, and exhaust guide have the same parts numbers for both shaft length models (per the parts site I'm using). It's obvious from pictures that the upper casing is a separate part between the two models though. I would also think that the driveshaft would have to be different as well. Can anyone help set me straight on what the differences are?

One other thing....I was looking at a video of a 1999 25hp 3 cylinder model too (as ad had it listed as 25hp, had 25hp decals, and had 3 cyl) since there wasn't a 3 cyl 25hp model in 1988 and surprisingly the two motors looked identical under the hood. Would a 1999 3 cyl 25hp and 1988 3 cyl 30 hp have the same powerhead? Just making sure this motor is not some frankenstein motor with a different powerhead than the model plate lists.

 

[scout-j-m]

After looking an another parts site, I am seeing that the upper casing and driveshaft have different part numbers for shaft length which makes sense. Still need to know what all else is required though.

 

[raczekp1]

https://www.youtube.com/watch?v=8DRVuYdq098&t=3s

 

[scout-j-m]

https://www.youtube.com/watch?v=8DRVuYdq098&t=3s

Thanks! That was an awesome video. I have found some places where you send the midsection off to do that work for you but pricing is very steep (like $750+ US dollars). I could possibly tackling the cutting by myself, but would have to get the milling done at a machine shop as well as find someone who can weld aluminum for me. I'd rather swap out for a short shaft midsection though. Cutting down the water tube and driveshaft wouldn't be too big of a deal for me. Finding the 15" leg is another story though.

 

[scout-j-m]

On the same subject motor...can anyone tell me what lower units from other models are direct bolt on? No luck in locating a 25/30 hp lower at a reasonable price but noticed that the 40/50hp 3 cylinder models of similar years are way more abundant and priced much better.

 

[racerone]

Impressive work to say the least.------Done in a " low overhead shop " I would say.-----Not sure how the alignment between gearcase and crankshaft was kept / checked ?

 

[raczekp1]

upper surface of midsection was the base for the miling.
down part was fitted for milleg surface.
look for other movis of this shop.
They are good.

 

[scout-j-m]

Impressive work to say the least.------Done in a " low overhead shop " I would say.-----Not sure how the alignment between gearcase and crankshaft was kept / checked ?

How much room for error is there between the two? I'd imagine if close it would still mate/bolt up but would it do something like destroy the driveshaft to lower seal and bearings after relatively short amount of run time?

 

[scout-j-m]

upper surface of midsection was the base for the miling.
down part was fitted for milleg surface.
look for other movis of this shop.
They are good.

Does it say anywhere in the description how much labor time it took in total or what the cost was? English and very mild Spanish is all I speak.

 

[raczekp1]

you can send them private mesage by youtube. they speak english.

 

[scout-j-m]

I bought this motor. I will likely just hold out hope for finding a short shaft midsection if I try to convert lengths. For the time being I will use a jackplate to make it work with my 15" transom. From here I guess I will buy a factory service manual and study up on the ins and outs of this model so I can fix the lower and verify some stuff like the link and sync on it and timing advance.

 

[raczekp1]

here is timing and carb synchronization
https://www.youtube.com/watch?v=peryTN14P-Q&t=10s

 

[scout-j-m]

Thanks again

 

[scout-j-m]

I found a guy who has a short shaft mid, drive shaft, shift rod, and water tube all together. I assume this is all that would be needed. Since my lower needs a new forward gear and shift rod, I have already pulled the bearing carrier and the driveshaft and pinion gear must also come out in order to change forward gear. This would allow me to swap driveshaft sizes while in there. Is swapping midsections terribly difficult? Appears like I would have to remove lower (already done), remove 6 bolts holding down power head, lift power head, remove mid at connections to the swivel tube, install new mid, re-attach powerhead with new gaskets. Doesn't sound too terrible especially if I have a hoist to lift and hold the head.

 

[racerone]

Put your power head onto the short mid section.----Would save a lot of work.

 

[scout-j-m]

Put your power head onto the short mid section.----Would save a lot of work.

This mid is simply just an empty casing, no swivel tube/bracket, lower cowling, exhaust tube, tiller, etc.

 

[racerone]

Post # 14 talked about MIDSECTIONS and now you appear to say you only have the exhaust housing.

 

[scout-j-m]

Post # 14 talked about MIDSECTIONS and now you appear to say you only have the exhaust housing.

Yeah, sorry... poor terminology on my part. Anytime I have said midsection here I have really been referencing the upper casing. So to clarify, I have a complete long shaft outboard and am in the process of purchasing a 15" driveshaft, 15" upper casing, 15" shift rod assembly, and 15" water tube, with intent of switching all out for the factory long shaft parts.

 

[raczekp1]

long shaft parts you can sell

 

[scout-j-m]

long shaft parts you can sell

Yeah I plan to list them online to try to recoup the money to at least break even on the cost to convert it lengths. Not sure what the demand is but maybe they will sell if I'm patient.