L150XTRT runs great on land but not water!

[99yam40]

Spent some time cleaning them. Yhe one is very pitted does that say anything about one of the cylinders?

only thing I can think of to cause pitting is water/rust

was it Rodbolt that said something about burning water will leave some kind of deposits on the plugs?

[JDWOODBURN33]

I know the fuel water separator I replaced was in really bad shape maybe it had been letting water in. I replaced it and cleaned out the tank before I ever ran on the tank gas for fear of that. I cleaned the plugs really well with new ones on order. I have called in a mechanic to look over the engine professionally, i don't want to keep chasing small engine problems and miss out on the whole boating season. I feel like I can maintain a working engine but for some reason I can't mechanically get it to that point.

Installed a batery kill switch because something was drawing power with the ignition off slowly killing the battery. Trying to clean up 20 years of DIY electrians running copper wire throughout a boat. WTF. It has been a hassle but I'm learning all the little nooks and cranies of my boat.

When its done ill know its done right and has that sense of accomplishment even if I give up fixing the damn engine!

[JDWOODBURN33]

Old fuel water separator

[panasonic]

Old fuel water separator

Holy crap, that is bad. Well you know if someone left that so long as to end up like that, god only knows what else you are going to find with this boat and engine.

Do you have them correct and proper Yamaha manual for that engine? You need to link and sync those carbs.

I would be putting a borescope down in each cylinder and have a look for water getting in (steam cleaning the piston top)

[panasonic]

Have you checked the oil injection is delivering correct amount of oil? Those plugs look oil fouled to me.

[JDWOODBURN33]

Lol I wish I had a manual. I took the carbs off and cleabed them but I have to admit that I am a fuel injection kid. Never worked on carburetors so I don't know how to tune them. I called around for a mechanic hoping to get a professional to look it over.

So I scoped the cylinders for rust and corrosion and they looked good sprayed a little oil in them anyways before I started the first time.

Some suggested that I look into the oil delivery, when I did I found that some wernt connected and just sprying on the block. I don't know how to set the amount they deliver?

[panasonic]

Go to Yamaha publications and get the service manual for your engine. You can get a PDF version for approximately $40. It will have all the information you need to set up that engine properly.

Once you have the manual and if you have trouble then, the fine folks on here will help you out.

[amahaork]

I really want to help fellow boater with old yami like mine.
Spark plugs are correct NGK BR8HS-10 (10 = 1mm gap)
Install new plugs, run some time, remove and examine
I can send yo a link to my service manual LIT-18616-01-13.pdf

[99yam40]

good idea to send email address in a PM so he can e mail it

[JDWOODBURN33]

jdwoodburn33@gmail.com

Thanks so much

[99yam40]

I mentioned PM ( privet message) because putting your e mail address in an open forum is asking for spam and maybe other things

[JDWOODBURN33]

Hey gents I had a mechanic come by tonight and look at the engine. He checked compression and I had 4 cylinders at 120 and 2 cylinders at 95. His diagnosis was that the motor was only useful for spare parts. Not what I wanted to hear but at least I know. Anyone have some home remedies I can try to build up more compression or has my boat sunk before I even got it out?

[TownsendsFJR1300]

Are the two low cylinders adjacent to each other?

If so, I'd be checking the head gasket..


.

[JDWOODBURN33]

Yes they are adjacent, I've been reading up on causes and it said if they are beside each other probably a gasket to blame. I also found two oil injection lines disconnected not sure but they could be for those two cylinders and then who knows when the last time they got oiled. He also tested cold and most guys online say the engine should be warmed up first.

Im starting to think all hope isn't lost just yet but I definitely have to dig further into the engine.

Is there any rationale to only change one head gasket if thats the case? I was also looking and found that there's a head cover gasket and a cylender gasket?

Screenshot_20200630-100548_Chrome.jpg

[TownsendsFJR1300]

I'd pull that particular head first and see what you got. Very likely a blown head gasket.

You'll need the gasket for the water jacket gasket as well (should you proceed with the head gasket replacement)

Being a 25 year old engine, broken bolts are a real possibility.


I wouldn't touch the other head unless you found major built up corrosion / crap in the water passages (clean those out of course) which can/will eventually clog and cause the engine to go into limp mode.

A leak down test would also help determine a leaking gasket.


I think it's kinda s...y that tech is telling you it's a parts machine W/O digging a little deeper. Should you find a blown head gasket, I'd be finding another tech as he for what ever reason,
he couldn't/wouldn't tell you/look at this very real issue..

.#27 is the head gasket, #30 is for the water jacket:


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