L150XTRT runs great on land but not water!

[JDWOODBURN33]

New boat owner here. I have a 1995 Century with a Yamaha 150hp OB L150XTRT. Boat had sat for approximately 6 years. Went throught all the basics: spark fuel and air. Boat runs perfect in the yard however PROBLEM: I got it out on the water yesterday started up and ran fine for about 30 minutes then it bogged down and I eased off the throttle and put it in neutral it came back to life and as I was heading in it bogged down again but this time died completely. I could get it restarted but had to throttle up (in neutral) and as soon as I tried to put it in gear it would die when the RPM's decreased. I ended up starting the engine with the throttle ³/⁴ open and quickly shifted to neutral and quickly threw it into forward. It took off like a bat b out of hell but I made it back to the dock. I am totally confused if anyone could offer suggestions I would appreciate. Thanks

[99yam40]

did you drain and clean the gas tank and rest of fuel system before firing it up after it sat for 6 years?
did you make sure the oil injection system was clean and functioning properly?

[JDWOODBURN33]

I removed all the old gas ran seafoam through the system. I have not checked the oil system. I'll have to start reading up on how it works

[TownsendsFJR1300]

As 99Yam posted, "clean the gas tank and rest of fuel system" this includes ESPECIALLY all the carburetors.

Varnish from old fuel collect and clogs up very small jets and orifices.

Partially clogged carbs may allow the engine run somewhat out of the water but with a load (pushing a boat), all bets are off.


The link to your carbs / parts break down. Pay especial attention to the main and low speed jets:
https://www.boats.net/catalog/yamaha...xrt/carburetor





An extreme example of the effects of old fuel (a small engine I repaired):

[JDWOODBURN33]

@99Yam thanks for the advice, I was checking the oil injection and accidentally pulled one of the hose apart. Had to remove the oil reservoir and the starter to replace but thank goodness I did I found 2 other oil lines that weren't connected. Just spraying oil on the block. Thanks who knows how long that would have gone unnoticed.

Townsends I will look into the carburetors and let you guys know what I find. Before I ran it on the new gas in the tank I ran a gallon of gas with seafoam let it sit overnight and then repeated. It was suggested that that would do a quick cleaning. I just hope mine don't look as bad as the picture!

[TownsendsFJR1300]

Seafoam works pretty good but fully draining the carbs(with bowl drain screw) is the way to go for long term storage. Storing with Seafoam in the carbs
would have been good..

Yours won't be anywhere's near what I posted (that one had old fuel, for years, going into the carb, evaporating, making varnish, re-peat).

Some jets have VERY, very small holes that go sideways thru the jet, those must be clear. The holes are so small my jet cleaning tool is too large for them.
I end up cutting ONE STRAND off a hand held wire brush and clamp in a vise grip. That's the only thing that fit thru some such, small orifices..

Lastly, to help clean the carbs once running decent I use Yamaha's RingFree. It's not a stabilizer but a fuel system cleaner(and top end cleaner).
I use it in every machine I own and work on with very noticeable results.. Not cheap but much cheaper (and faster) than a carb rebuild kit/ cleaning...

[JDWOODBURN33]

@townsends I spent the day tearing apart and cleaning carbs. I didn't replace anything I assumed someone had had rebuilt the cabs previously. Numbers were etched onto the carbs 1-2-3. All the gaskets were in good shape and for the most part they were pretty clean! There was a collection of debris in the tank and some miscellaneous debris shooting outward from the air chuck in tight cavities. Oh the last damn screw I took out of the bowl broke off Anyhow put it all back together and it is running better, constant idle RPM's. However I did a check at the exhaust, held a empty bowl to collect the water coming out and there was an oily film on top of the water is that normal? I will test it in the way this weekend and see if all the work is paying off

[JDWOODBURN33]

20200624_175009.jpg

[TownsendsFJR1300]

Glad there's improvement. I would still run some RF which should help with overall performance.


Re oil, it IS a 2 stroke and oil is pumped into the fuel/motor and eventually out the exhaust.

With the engine sitting/idling/ etc once you brought it back to life, I would expect to see some(NOT a bunch) oil coming from the exhaust.
I suspect it's fine.


If you have any running issues once on the open water, I wouldn't keep pushing it.-IF there's still a clog in a carb, you don't want it leaning out a cylinder and damaging the engine..


BTW, what screw broke off? Just one of the outer bolts holding the bowl on?

.

[panasonic]

Have you cleaned the fuel tank, changed filters...ect? No good to have clean carbs only to pump dirt right back into them.

[99yam40]

Have you cleaned the fuel tank, changed filters...ect? No good to have clean carbs only to pump dirt right back into them.

depends on how the tank was drained, draining a tank may not get everything out of that tank if the normal pick up line is used,
there will be stuff still in the bottom of tank,
but hopefully the filters will catch most of it

[JDWOODBURN33]

@All, yes I pumped out all the old gas refilled with 93 octane and a fuel stabilizer. I replace the fuel water separator and the fuel filter. I'm not sure what kind of pickup I have but I figured most debris wouldn't get past the separator and fuel filter?!? How hard is it to tune the carbs?

This was the screw that broke off. Not such a big deal drilled it out and replaced. Wish everything was that easy!

Thanks everyone for the help. Getting this engine running right is the only thing holding us up. The family is really itching to get on the water.
20200625_210915.png

[JDWOODBURN33]

Hey gents since the boat was running a little rough with quite alot of oil/fuel mix coming out of the exhaust I decided to look at the plugs. Any thoughts it seems like they are pretty wet?

[JDWOODBURN33]

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

[TownsendsFJR1300]

Those plugs have seen better days, replace them..

What are the gaps NOW vs recommended? (IE, how worn are they)..


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