yamaha sterndrive

[ebbtide954]

I've recently acquired a 91 ebbtide with a 350 and yamaha stern drive. From what I've researched the drive is almost as good as the anchor that came with the boat. I would like to make it work and make it reliable as possible though. I finally got the boat fired after chasing wiring and fixing the timing and firing order.. also carb adjustments. It is hammered knocking and squealing like crazy. So I will be pulling it and installing a new short block. First question is how much power can this unit handle hp wise. Second, what if anything can I do to make it handle hp better. Third, what problem parts do I need to look for when I get the motor out.etc etc. This is my first boat I have owned. I'm rather knowledgeable on cars and motors. I've installed a couple motors in baja's with merc outdrives at the performance shop i used to work at but any advice would be greatly appreciated. I will probably ask a bunch more dumb questions in the future so sorry in advance.

 

[Capt Ken]

Re: yamaha sterndrive

If you want it to handle more power, swap over to a Hydradrive. That's what Yamaha did.

 

[ebbtide954]

Re: yamaha sterndrive

I wasn't wanting to get crazy just a very mild 300-340 hp

 

[ebbtide954]

Re: yamaha sterndrive

Also from my creeping on this forum you seem to be the go to guy on these things. The guru himself. I would like if at all possible keep this drive in here. With it also being dependable. Any... I mean any type of pointers or parts to get for this thing while the motor will be out will be GREATLY APPRECIATED.

 

[Capt Ken]

Re: yamaha sterndrive

Never had anyone try to hotrod one so really don't know how much HP it will hold before it goes bang. The vertical driveshaft appears to be the weakest link. You're looking at it so you tell me what you need. I know you will need a gasket kit to remount the drive. Probably a water pump kit also. Just try not to break too many parts.

 

[Walt T]

Re: yamaha sterndrive

Wow Ken! You've reached Guru classification! You must be so proud!

 

[Capt Ken]

Re: yamaha sterndrive

I'm a legend in my own mind

 

[Bondo]

Re: yamaha sterndrive

I'm a legend in my own mind

Ayuh,.... My ole lady tells Me that All the time,...... :lol: :laugh:

 

[ebbtide954]

Re: yamaha sterndrive

Lol! I wasn't trying to come off like a dbag. I was simply complimenting you. As I know nothing about the yamaha and honestly know very little about out drives in general. I know enough to see the obvious. I have built a motor and will be swapping hopefully in the next couple of weeks. Its just a standard 355 with a very mild cam and I've polished the heads of and port matched the heads to the intake. I will be using the same quadjet. I was just looking for any tips and pointers on these things like problem areas/ parts since I haven't took the motor out yet. I have noticed some play in the steering on it. Also this might be another non intelligent question can you thru hull exhaust with the yamaha manifolds? Thanks and sorry for coming off like an acehole if I did

 

[Capt Ken]

Re: yamaha sterndrive

You didn't say anything out of the way and no offense taken. Actually guru is one of the nicer things I've been called. It's just that Walt doesn't have a life other than collecting belly button lint.

 

[Walt T]

Re: yamaha sterndrive

I do too! I collect my dog's crap in bags.

Ebbtide, Craptain Ken and I go way back. You can't possibly offend Ken he has been called way worse by better. He's been banned in every forum on the Net and the only reason iboats lets him post is because ain't nobody else know anything about Yamahoos.

 

[ebbtide954]

Re: yamaha sterndrive

Good deal. Id hate to offend anyone on here being a newbie and pretty much mentally incapacitated when it comes to these yamahas. So I was thinking about doing either a side exit exhaust or a thru hull, Didnt know if it was possible on these. I'm also trying to find a engine coupler, I know its probably going to need replaced. It's a good looking boat and I want to keep it looking good and reliable as possible.

 

[Capt Ken]

Re: yamaha sterndrive

You can do a thru hull out the transom if it's high enough above the water. The original exhaust has flappers inside that prevents water from surging back into the engine when not running. That happens when you have those 400 pound bathing beauties sitting on the stern. As for the couplers, we carry the replacements in stock.

 

[Maclin]

Re: yamaha sterndrive

I can vouch for the "way back" between those two You ought to read some of their stuff on Boat Dr

Seriously, the tech advice from Guru Ken, especially on Yamaha, is top notch, and Walt's is up there too, can't do much better!

 

[bajaman123]

Re: yamaha sterndrive

I can vouch for Captain Ken myself, all joking aside he is the ONE guy left in the Known Universe with the tools, parts, and most importantly, EXPERIENCE with these Yamaha outdrives.

I've had my 454 powered Yamaha Hydra Drive since new in late '91. It has been absolutely trouble free, until I found a place where "draft exceeded depth", lol. Ken fixed my right up. The Hydra Drive is phenomenal, just not many of them left in the U.S., though the newer versions are HUGE in Europe and the U.K.

As for the smaller outdrives, I've known two other guys with them, both were 5.7 liter 4 bbl powered boats, ~260 hp stock. One guy put thru-hull exhaust on, did an Edelbrock Performer Marine series manifold and carb replacement when he did a cam upgrade. The engine was never dyno'ed to my knowledge and the cam wasn't the best choice as it was all in the top end, but the Baja 188 Islander it was in ran low '60s at around 5500 rpm. I was around this boat for about 5 years and it never had any problems. So I wouldn't shy away too much from up to 300 hp.

 

[Capt Ken]

Re: yamaha sterndrive

Damn, I actually fixed one. I amaze myself sometimes.

 

[ebbtide954]

Re: yamaha sterndrive

Thanks guys. I've been stuck out at the rig for sometime now and days off have been far and few between. I snagged a set of vortec heads and got a good dual plane intake for it. The interior is completely gutted right now and is currently being reupholstered, after cutting and making everything from new marine wood........ EXPENSIVE project so far. So ken, you said I can get parts that I need from you correct. Well I would like the gasket set for the outdrive for sure and anything else you think I should get while im that deep in there. The knockkng motor is still installed. I fired it up the other day to double check operation on the outdrive, trim, shifting etc. I noticed it was running rather hot for a boat around 210 with good muffs on. Could be from the trashed bearings making excess friction. Also what alignment tool should I use or do I need to use one.... probably another dumb question. Thanks again guys everything has exceeded my expectations on help. You all are great.

 

[Walt T]

Re: yamaha sterndrive

Trashed bearings don't cause that. They can cause all manner of other problems such as gnashing of teeth, insufficient funds overdraft fees, finding out how comfy the couch is all night, Wait... No that's booze that does all that. Well, not the running hot part. Booze wont do that.

 

[ebbtide954]

Re: yamaha sterndrive

Anybody??? Please help me I'm retarded and own rare gem that needs some polishing.

 

[Walt T]

Re: yamaha sterndrive

PM Ken if you need him. Overheat at idle on the muffs can be as simple as not enough water present or a bad impeller. Definitely chack the impeller before you go out again