replace all carbs

[colayn]

I have a 99 Yamaha Vmax P150tlrx. Been in the shop over a month due to no top end power. Carb rebuilds, new fuel pumps, decarb engine, plugs.
Got a call from the mechanic yesterday and he said they finally found the problem. They put all 3 carbs on a flow meter and they are working very erratic.
He said Yamaha had a problem with some ports in these carbs that can't be cleaned and all 3 have to be replaced due to debris inside.
Is he pulling my leg (worst my wallet) ?

Appreciate the help

 

[rodbolt]

Re: replace all carbs

both
look on your technicians wall.
if there isnt certificates for fuel and electrical at a minimum, leave.
Yama DID NOT EVER have a problem with the carbs.
yes trash can get in the fuel inlet area and its hard to clean. later carbs had a clean out port that can be added to the earlier carbs per a tech bulliten.
tells me someone aint looking at the bullitens.
also ask to see test wheel YB1626.
if they dont have it go find a real shop.
never seen a shop with a flow meter, they are rather expensive and I have ben in a lot of shops over the past 35 years or so.

 

[colayn]

Re: replace all carbs

Rodbolt,
You are right on as to were the problem is, the inlet side of the carbs.
I am pretty discouraged right now, looks like I am buying 3 new carbs. Yesterday I told them to get the parts, then I tossed and turned all night thinking this is just not right. I am not Yama certified, but have been working on cars, tractors , mowers etc for most of my 47 years.
Anyway I went to the shop today and their "flow meter" is the cleaning tank.
They said Yama tech showed them how to check the inlet side by removing floats and needles and pumping fluid thru the inlet.
I admit there is a problem, the flow from the seats is very erractic.
My carbs have the updated access to clean the main passage but they can't get anything out of it.
I agree with the cross passaged being sealed from the factory makes it difficult but there as to be a way.
And why after 11 years would it hit all 3 carbs at once?
The filter on the fuel lines is as clean as new.
Anyway, I just got to suck it up, but I have learned a lot.

 

[rodbolt]

Re: replace all carbs

thats close to 1400 dollars worth of carbs based on a test thats IFFY at best.
its so IFFY that I dont do it and never have.
to many variables that I cannot control.
however I have never replaced a V4 or V6 carb unless it sank and was saltwater damaged beyond repair.
thats the beauty of YB1626 on your engine.
install it, back it down the ramp and throw the throttle wide open.
if it cant spin to 4600-4800 I can now trouble shoot both fuel and ign systems quickly at the problem load and RPM. if it can I can quit chasing ghosts and go find the hull or prop issue.

 

[colayn]

Re: replace all carbs

for my education what is a YB1626? I tried to google it and can't find anything.
Can you do the same thing with a dyno ? That is what the shop has.
They way the finally determined is was in the carbs was by running down the lake and spraying fuel into the carbs.

 

[rodbolt]

Re: replace all carbs

test wheel YB1626 is a device that Yamaha engineers desingnd to replace the propellor giving a known load and no thrust on the engine.
its very usefull in finding problems at or near WOT and finding hull or prop issues.
3 carbs on a single engine is probably more carbs than I have replaced in 35 years.
if your carbs dont have the fuel inlet clean out ports then they can be easily added as per the technical bulliten.
I use a small wire brush set, can be purchased from snaop on and a few other tool places, to clean the transfer passage that goes below the needle seats.
long before I spent a customers 1400 on carbs I would be checking fuel supply and cleaning that passage.
would be a bummer to drop 1400 on carbs to find an ar leak or a defective fuel pump.
but its hard to convince me all 3 carbs failed.

 

[colayn]

Re: replace all carbs

not trying to convince you, I agree myself.
Problem is I already gave them permission to get the parts which will be there Monday.
I am as mad at myself as I am with them.
Again, for my education what do they use the dyno for? Just to check HP or can they put a load on the engine with it?

 

[boobie]

Re: replace all carbs

As I used to work for a Yamaha dlr a few yrs back Rodbolt is 100% correct. I don't think this dlr you have knows what he is doing. And yes there is a bulletin out there that tells you how to install a plug in the carb to get at that passage underneath the seats in the carb to clean them. I know it wouldn't cost $1400 to do the job. Maybe you should find a decent dlr. Sounds like you got some young kid working on it that doesn't know what he's doing.

 

[seahorse5]

Re: replace all carbs

Your 1999 motor already has the screw and gasket that allows access to the fuel passageway from the inlet fitting to the float valve seats. I believe Yamaha added the access screws in about 1992 or '93.

I would have another discussion with your mechanic about cleaning out the carbs in that inlet fuel area. You will see the brass slotted-head screw located on the side of the carburetor body just above the float bowl gasket surface.

 

[rodbolt]

Re: replace all carbs

yes the IDC 2003 series dyno is useful.
yes I owned one for years that I ordered custom with 11ft hoses and a pump that could test counter rotation engines, at my divorce I sold it to Rons marine in portsmouth Va to pay for the kids orthodontist.
had to do that or lose it anyway and I can still use it.
had it setup in the truck so I could dyno test mobile.
your P150 should pull close to 3000 PSI at 5000 RPM.
draw back is its hard to keep the engine cool on a dyno when extended running is done.
however I dont think carb replacement is warrented in your case.
its also what gives the marine industry a bad name and leaves customers with bad memories.
as bad as I hate regulations I am leaning more and more to regulating marine techs like aircraft.
poke-n-hope is NOT a reccomended trouble shooting method.
yes the needle seats in your carbs are fixed non replaceable,ya cant convince me all 6 failed.
yes sometimes I spray premix down the carb to isolate a cyl, usualy I can tell which cyl is down with my Kv tester.
if I sprayed all 3 carbs and got a positive engine response I would be looking at fuel supply.
these carbs are dirt simple and if not water damaged are bullit proof.

 

[colayn]

Re: replace all carbs

Yes, my carbs have the clean out, I mentioned that in my 2nd post.
Thinking I will call them today and see what it will cost to stop working and I will just to pick it up.
Really regret I ever gave the permission to order the carbs, (which aren't there yet)
The guy in the shop working on my boat is "Yamaha certified" and they have a good reputation around here. But he should know just from pure logic there is not 3 bad carbs on that engine.
And no it has never seen salt water and never been sank.
They have been dipped in commercial carb cleaner once, for about 1 hour. Found out later that is a no/no with these carbs.
Could that be some of the problem?

 

[colayn]

Re: replace all carbs

since this is a "yamaha certified" shop
Is there anyone at Yamaha I can call and ask them to talk to the guy before they receive the new carbs ?

 

[rodbolt]

Re: replace all carbs

yamaha certified can mean anything from at least one person did the video course to they employ a master tech which there arnt many of us.
nope, no sense in calling yamaha your dealer is simply a franchise.
always look on the wall for training certificates.

 

[colayn]

Re: replace all carbs

Rodbolt, can you tell me the part number for the Snapon wire brush set you use to clean that passage?
I think I will pay to have the carbs sent back and do this myself

 

[rodbolt]

Re: replace all carbs

dont know it, but any small brush will work.

 

[khenry]

Re: replace all carbs

You should not have to pay to cancel parts ordered. Its only going to cost a couple of bucks to send them back. And after all they have put you through, should take care of it.