1999 F50TLRX Noise

[ChuckB1954]

The old carbs are probably usable, but have much internal corrosion, like they were full of salt water at some point.Very nasty looking. I will remove the carb assembly and examine the #2 carb. I will soak it overnight in the carb cleaner kit. I have had great results with it in the past. I should have taken 99Yam40's advice and checked them all before I installed them. A case of logic being over ridden by wishful thinking.

As far as the cam lobes, I have examined them in the past and saw no issues. I think I would rather cut my hand off than remove that cover again! I have only had it off at least 4 times... maybe 5! I have lost count.

[ChuckB1954]

it would be interesting to know what cylinder chunked a rod on the motor that those carbs came from.

I would go thru all of the carbs, but that is just the way I roll.

hope cleaning the carbs solves you problems.

have to wonder what chewed on that stater , and where /why all of the rust up on top. water should not get to that under normal situations.

I didn't want to say it, but it happened when I pulled the flywheel off. It fought all the way. I had to put the puller back on. Would not come off by lifting with my hands. Evidence of the plastic isolators scraping can be seen in the rusty flywheel photo. Looking back, I should have spun it around while lifting after getting it past the woodruff key. I probably could have avoided it. No apparent harm done, other than the isolators.

The way the original carbs look on the inside makes me think this engine was under water at some point. Not the original engine for this boat which came with a Yamaha 55HP two stroke when new. That 2 stroke is now on my friends boat. The guy I bought the boat from mentioned that he had no history on the my engine.

EDIT: I just sent the original seller of these carbs a message. I told a white lie that they cleaned up great. I didn't want him to think I was not happy with them and was trying to open up a dispute. Hopefully he will reply.

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carbs.jpg

[TownsendsFJR1300]

Yep, that engine went under water...
The flywheel and carb corrosion sure points that way...


And apparently sat some before addressing the water intrusion, jeez...


With that said, I have to think of what other part, once submerged, could/would potentially cause your issues now..


A new can of worms to contend with..

[ChuckB1954]

It was raining on and off.. I would uncover my boat and within a few minutes it would start again. I gave up.. I went on my computer and started looking at my carb pictures and then a thought came to me.. That cylinder is probably getting no gas because the butterfly is fully shut or close to it. Not enough fuel causes backfires to occur in the intake manifold. The exploding mixture then vents through the carb. I went outside and sure enough, that was the case. I verified by turning the #2 sync screw CW. Firing on all 4 cylinders now.

Although there are other ways with a tach that I could try, I think I should get me a set of gauges to synchronize the carbs.It would make it easier and much more accurate.
I was thinking about this set on Amazon. The price is right, but is there a better choice?

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Description:

- Brand New and High Quality
- Excellent quality vacuum gauges enable easy synchronisation and balancing of motorcycle carburettors.
- Complete kits with vacuum gauges, hoses, adapters, mounting plate.
- Each gauge has damping control and calibration control.
- Easy to install, instructions is not included

Specification:

Vacuum gauges
- Material: Plastic
- Diameter: 70mm/2.8 inch
- Height: 25mm/1 inch
Mounting plate
- Size(L x W x H): 310 x 100 x 20mm/12.2 x 3.9 x 0.8 inch

Package Includes:

1 Set Carburetor Synchronizers

[99yam40]

in post 28 you said you screwed #2 mixture screw all the way in,
did you bring it back out to spec?

as far as vacuum gauges go ,I have not had to use them ,but seems like I read that without enough restriction in the lines they can bounce all over making it very hard to get readings.

I bet between the sync screws and the mixture screws it may take some time playing with things to get them all set properly

hopefully the manual will guide you

[ChuckB1954]

in post 28 you said you screwed #2 mixture screw all the way in,
did you bring it back out to spec?

as far as vacuum gauges go ,I have not had to use them ,but seems like I read that without enough restriction in the lines they can bounce all over making it very hard to get readings.

I bet between the sync screws and the mixture screws it may take some time playing with things to get them all set properly

hopefully the manual will guide you

Yes, the ballpark spec is 2 1/4 to 2 1/2 turns out.

I have been researching gages. Some complaints about the cheap ones are they are not calibrated to each other. Most of them have a dampener to lessen fluctuation, but I read complaints that it doesn't work that well. Kind of discourages me from purchasing them.

My friend has a nice set of vintage mercury gauges. He stated that he will sync my carbs for me. I have a couple ounces of mercury that he needs. The only other machine I have with more than one carb is my '76 triumph Bonneville. All my other bikes have singles, so this would probably be the best route to take since I would probably never need them again.

[TownsendsFJR1300]

This one is about the best you can get, Morgan Carbtune: http://www.carbtune.com/

No liquids, no adjustment to the tool needed. Highly recommended and extremely accurate.

I've had mine about 10 years (now available for purchase in the states). I've used it on motorcycles mostly, also on my F150.



Mine, working after doing a valve adjustment on my Yamaha FZ6 motorcycle:

[ChuckB1954]

This one is about the best you can get, Morgan Carbtune: http://www.carbtune.com/

No liquids, no adjustment to the tool needed. Highly recommended and extremely accurate.

I've had mine about 10 years (now available for purchase in the states). I've used it on motorcycles mostly, also on my F150.

Definitely a nice one you got there! I couldn't justify the price though. I will probably never need one after I sync my Yamaha carbs.The Triumph is the only thing I might use them for, but it has dual throttle cables, which makes it easy to Sync.

I took the cheap way out and found a used one one ebay. It appears that the adapters are 5MM and I need 6MM though. I can work around it though.

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[ChuckB1954]

Just an update... Been quite busy lately, but finally found some time to work on the engine. Got the carbs synced and the engine is running great! I took it out today and really have no complaints. At WOT, about 4800 RPM's, my top speed is 31 MPH. Engine purrs like a kitten!

[pstephens46]

Just an update... Been quite busy lately, but finally found some time to work on the engine. Got the carbs synced and the engine is running great! I took it out today and really have no complaints. At WOT, about 4800 RPM's, my top speed is 31 MPH. Engine purrs like a kitten!

What is the WOT rpm range for that model? Is the motor trimmed up at all?

[pstephens46]

Just an update... Been quite busy lately, but finally found some time to work on the engine. Got the carbs synced and the engine is running great! I took it out today and really have no complaints. At WOT, about 4800 RPM's, my top speed is 31 MPH. Engine purrs like a kitten!

No wake zone?

[99yam40]

I thought most 4 strokes should run 6000 at WOT.
OP needs to look for another prop, or motor is not running as good as he thinks

[ChuckB1954]

Initially It had a 14 pitch prop and it ran a little slower (28 MPH) at less (?? I forgot) RPM's. I traded props with a friend who had a 13 and the speed/ RPM's increased. I probably need to drop down to an even lower pitch. The numbers previously posted were optimized playing with the trim.

[ChuckB1954]

No wake zone?

That stretch of canal is posted a no wake zone, although the speed in the video slightly exceeded it.

[ChuckB1954]

I'm thinking of going with this prop: Aluminum Prop - 3 Blade 11.63x11RH (69W-45947-00-00). Any thoughts?