Help with yamaha l4 3.0 on 1993 VIP Vision

[Nahbrah]

1993 VIP Vision with Yamaha L4 3.0 sterndrive

I've recently acquired a project boat from a friend that sat up for 9 months. After changing the oil/filter, lower unit fluid, and greasing everything she cranked right up to my surprise. It was also having some shifting issues that were solved with some new cable ends, cable adjustments, new upper gasket/seal, and realigning the shifting fork. Started her up on muffs and everything seemed to work smoothly, so I decided to take her to the launch and see what she does under pressure. Started up first crank in the water and sounded great so I tied off at the dock and went to replace the trailer bunks in the parking lot. Came back and when restarting I had to go full throttle just to keep it running. It stopped running after each restart until ultimately puking oil out of the breather hose at the flame arrestor. I called it a day on that note. Came home and did a pressure test and got 120 psi on all four cylinders surprisingly. Replaced the spark plugs and halfway broke down the carb to clean/check for good gas flow through needles and ports. Noticed the gasket/seal on the top half of the Rochester 2 barrel was torn and missing a 1/2" section. While awaiting a carb rebuild kit and new impeller I'm trying figure out what else could be wrong that I need to explore...seems like the gas/air ratio is off. I have a Clymer manual but can't seem to find any decent pictures of the carb and throttle connections (mainly the return spring side) to know if it was assembled properly by the previous owner. Sorry for the lengthy story. Also, any help with model and brand of an aftermarket impeller?

 

[Scott Danforth]

There is little to any yamaha parts support.

120 psi is low, as in time to rebuild low

May be better off finding complete mercuiser or volvo penta 3.0/drive

 

[Nahbrah]

Thanks Scott! I'm becoming aware of the difficulty to find parts. I don't expect it to ever run extremely well without doing some serious work and investing $$$. It truely isn't worth the money it would cost to fix/replace what REALLY needs to be fixed/replaced. My hopes are to spend very little, take it out a few times, and sell it. Mostly for nostalgic reasons to see it have atleast one last lap. Is that just an unachievable goal at this point?

 

[Scott Danforth]

the fact that it is pushing oil out the valve cover breather and the compression is that low means the motor is toast - burnt toast. the fact that even normal service parts for the yamaha are not easy to get means the drive is a non-starter.

find a mid 90's boat on craigslist near you with a rotten interior, rotten floor, other hull damage. they are sometimes even free - however usually about $500-$1000. pull the motor and drive out of it, put in yours and then dispose of the rotten hull, sell the trailer for a few hundred and you can part out the yamaha drive. that route may actually make you money.

 

[kenny nunez]

If you manage to find a donor boat the basic engine has a lot parts that can be used over. I believe the transom hole is the same as Merc & late Volvo. The cannon plug is the same so you can re use your wire harness over. Depending on your control box you may have to use the one from the donor. Steering should be no problem. In the meantime check that the fuel pump is not leaking and putting excess gas in the engine through the carburetor.

 

[DeltaHoopie]

Hi folks, I'm new here. I was just trying to find info on my Yamaha L4 3.0 Hope not to step on any toes so here goes.
Did you check compression with WOT as you cranked it? Just asking. Made a difference on one my tests.
I also just recently got a pontoon w/ a Yamaha L4 3.0 She runs great. However I'm getting a little nervous about the scarcity of parts available. I have e-mailed Capt.Ken at NelsonMarine in PCB, awaiting a response on his opinion of these Yamaha's.
I have trouble going into neutral sometimes (usually when I'm docking of course). Since you had shifting issues do you think adjusting the cable ends will help? The interrupter switch works when manually actuating it.

 

[Tinman2809]

I have a 4.3 Yamaha..stock up on parts man...take care of her shell last..i have a spare set of manifolds..t stat housing etc

 

[Nahbrah]

I did not have WOT for the compression test! What were your readings? Please tell me I just screwed up on the test and my engine is not fried afterall!!

My cable ends were cracked so I did have to replace and readjust them to the manufacturers specs. That helped, but I could tell that something in the outdrive or shifting cable was still ?catching? when I shifted. It was taking far to much force to actually shift, which is how I assumed the cable ends cracked in the first place.

I then removed the outdrive and found a lot of rust that had to clean and regrease all the moving parts (mainly around the shifting fork). Still had issues but shifting was getting better.

Again I removed the outdrive and wet sanded the shifting fork and bottom of the shifting rod where it seats in the cup, very very well. Also carefully dremelled down the edges of the shifting fork to maybe help for a smooth shift with no possible ?snags?. Again I cleaned and regressed everything. And now it shifts flawlessly!!

I took the info I found on these forums and kind found my own solution. I?m an obvisously not a mechanic, so please take this info for what it?s worth and form you own solution lol.