150 TXRY Fuel Problem

[bigboylk]

I usually use my boat at least twice a month all year long. This year I haven't used the boat since September because of a bad winter here in California.

I took the boat out last week and the boat was firing on five cylinders. Back to the dock and changed the plugs. Ran on six cylinders at 3500rpm for about five minutes and then back to five. Checked the plugs and had spark to all plugs.

Before I went out this week I tried to start the engine and it would not fire unless I used starter fluid. Once warmed up it started every time like normal. Boat fan fine for about five minutes, at 3500 rpm, and then back to five cylinders!

Since I haven't used the boat in seven months, I figure I may have bad gas. It is 10% ethanol fuel that I did not treat before storage. Also, I noticed that black gunk ran out of the exhaust hub of the motor over night. I have never seen this in the past.

Do you think it is bad gas or should I look into rebuilding my carbs or ??

[panasonic]

I usually use my boat at least twice a month all year long. This year I haven't used the boat since September because of a bad winter here in California.

I took the boat out last week and the boat was firing on five cylinders. Back to the dock and changed the plugs. Ran on six cylinders at 3500rpm for about five minutes and then back to five. Checked the plugs and had spark to all plugs.

Before I went out this week I tried to start the engine and it would not fire unless I used starter fluid. Once warmed up it started every time like normal. Boat fan fine for about five minutes, at 3500 rpm, and then back to five cylinders!

Since I haven't used the boat in seven months, I figure I may have bad gas. It is 10% ethanol fuel that I did not treat before storage. Also, I noticed that black gunk ran out of the exhaust hub of the motor over night. I have never seen this in the past.

Do you think it is bad gas or should I look into rebuilding my carbs or ??

I would say both, old gas and now dirty gummed up carbs. Need to get rid of the old gas and clean your carbs.

The black gunk is excess gas from cylinder(s) not firing washing out your exhaust for you.


You have a portable 5 gallon tank you can hook up to it and see if it runs any better with fresh gas?

What do you have for filters?

[panasonic]

They are going to want the exact model identification on the tag...thanks

[bigboylk]

I have a Yamaha 10 micron filter for the fuel. Next week I'm going to pump out the gas and rebuild the carbs and install a new filter.

The engine is a 2000 model 150txry with carburetors.
I suspect that the fuel in the carbs gummed up the jets. The engine has always performed flawlessly since new and has been maintained by me at regular intervals.

I've never gone more than a month without using the boat for at least two hours. However, this winter I did start and run the motor on the trailer every three weeks or so! By the way, the engine has about 850 hours on the clock.

[rodbolt17]

while your doing the carbs do the fuel pumps and fuel lines.
any debris in the lines or the pumps will contaminate the carbs negating your work.
that and fuel pumps don't last forever and can blow up an oil injected Yamaha.

[bigboylk]

Rodbolt 17,

I took apart the fuel pumps and they look like new. However, the top pump cover was very loose and maybe it was sucking air?

I removed all 6 carb drain bolts and shot carb cleaner through the jets. No dirt drained out of the holes. I'm going to drain the old fuel and change filters and test before I service the carbs.

What do you guys think?

[TownsendsFJR1300]

I personally wouldn't gamble with potentially leaning out your engine (and DAMAGING IT) due to crap in the carbs.

You've been lucky so far.

Leaving un-treated fuel for extended periods of time about guarantee' you have at least one main jet crapped up, closed.

All JETS MUST BE REMOVED / inspected and if you can't see light thru them, DOES NOT COUNT.

Do you feel lucky?

[FabricGATOR]

Clean jets with solvents and shop air, I have been told that one is not to try to clear a clogged jet with a poker or piece of wire.

Hoppes Nitro Solve gun cleaner is something we use in aviation that I learned of at an IA continued education seminar for cleaning the continuous flow fuel injectors (solid brass like a carb jet)
Cheers

[bigboylk]

I ran the engine with a shock treatment of ring free. Pulled the plugs and the middle plug on the port side was almost black while the other five were a lite tan in color. These are new plugs.

I disassembled the middle carb and it appears to be clean without obstructions! Cleaned out the passages with carb cleaner and compressed air. I could see light through all jets.I plan on rebuilding the other two carbs but it seams that the problem is that middle port cylinder.

Do you think I could possibly have a problem with that coil! I tested all the plugs and they all had spark. Maybe that plug has a weak spark?

[FabricGATOR]

I used a golf ball once...

No kidding.
I had a 70 Johnson that had a carb acting up intermittently. There was a highspeed jet that would clog and then run, clog, run... eventually it would clog more than it would run. Any how, Becky and I were out one day and it was acting up, we had the dog with us at the river and he ran off in the woods chasing a fox or gopher tortoise one. When I was ordered' to go and get my dog I found a golf ball while walking the trails. We were headed back to the ramp and I had an ah hah moment.

I removed the front of the airbox as I had a few times before, and with Becky at the helm running 3/4 throttle, I shoved that golf ball into the air hole.
shLLllliii <~ I can't accurately spell the sound it made but just imagine a running engine with a golf ball shoved in a carburetor

An old trick taught to me by a neighbor. I used the running engine vacuum to force suck gasoline through the jets and passages to remove a particle of debris. He showed me on my old Impalla, he would pump rev the engine and while he was doing that haunched under the hood, he took his other hand and flat cupped the carb, basically making a flesh choke over the carburetor bore.
I've done that many times since from my mowers to a golf ball on my 1986 Evinrude inline 3 cylinder 70 HP. I was never able to get a good seal on it until then because of the shape and position of the flame arrestor. Walking in the woods, contemplating how to fix my boat, and coming across that round object, that made for this interesting story and yet another legendary tale few people believe.

[pstephens46]

No kidding.
I had a 70 Johnson that had a carb acting up intermittently. There was a highspeed jet that would clog and then run, clog, run... eventually it would clog more than it would run. Any how, Becky and I were out one day and it was acting up, we had the dog with us at the river and he ran off in the woods chasing a fox or gopher tortoise one. When I was ordered' to go and get my dog I found a golf ball while walking the trails. We were headed back to the ramp and I had an ah hah moment.

I removed the front of the airbox as I had a few times before, and with Becky at the helm running 3/4 throttle, I shoved that golf ball into the air hole.
shLLllliii <~ I can't accurately spell the sound it made but just imagine a running engine with a golf ball shoved in a carburetor

An old trick taught to me by a neighbor. I used the running engine vacuum to force suck gasoline through the jets and passages to remove a particle of debris. He showed me on my old Impalla, he would pump rev the engine and while he was doing that haunched under the hood, he took his other hand and flat cupped the carb, basically making a flesh choke over the carburetor bore.
I've done that many times since from my mowers to a golf ball on my 1986 Evinrude inline 3 cylinder 70 HP. I was never able to get a good seal on it until then because of the shape and position of the flame arrestor. Walking in the woods, contemplating how to fix my boat, and coming across that round object, that made for this interesting story and yet another legendary tale few people believe.

Not sure about the hand plug. I have seen flame pop out of quadrajet carbs when the engine backfires.....all's well that ends well though.

[scofflaw]

Back in the 70's that was known as the jewish tune up.

Now tell me me how restricting air flow to the motor is going to force more fuel through the jets. Not happenin.. it's the air flow and the venturi effect that allows the gas to flow....no air no gas with a carb

[99yam40]

plug off/restrict the air, it will increase the vacuum( negative pressure) in the carb throat, and it will suck on the fuel only, as that is what is available to be sucked on.
you do realize there is an opening in side the carb throat that leads to the main jet and fuel right?

[scofflaw]

Not buyin it.. So if it's sucking from the fuel side more than the air side, it should put the engine into an overly rich condition, right ? Ever see any black carbon coming from the exhaust when you perform this stunt... yah me neither.
Can also honestly say , I have never seen an improvement after this procedure.

[bigboylk]

Ok, rebuilt the middle carb and I ready to test in a couple of days.

On the trailer the motor seems to be firing on all six cylinders. I put a new plug in the port middle cylinder and after 20 minutes or running at 1200 rpm, the plug at a slight tan color like the other 5 plugs and was dry. Hope this corrects the problem.