80 Yamaha still not right, shop wants to replace all 4 carbs

[Beartrack]

The 80 Yamaha on the 22 Dory I bought a few weeks back is again back at the shop locally and they are now saying they've had the carbs apart 4 times to clean them and replaced the jets and all seals and are sure it's the carbs still. It's a 2001 motor with around 150 to 200 hours, and it had previously also had a carb job with the former owner.

The symptom is that it's popping and backfiring through the carbs randomly by cylinder up through about 2000 or so RMPs mainly then it pretty much smooths out. They already flat-filed the intake and mating surface and replaced that gasket too. And of course it just had new plugs, fuel filter, and water separator just done in the last few weeks.

They said that to get it running smoothly, even after re-synching 2 times, they said that the screws have to be adjusted out 2 1/2 turns out on one carb and as much as 5 turns out on the others and that indicates they need to be replaced as they should all be within a half turn. They want 2 grand to replace the 4 carbs and said all 4 should be done at once.

This sounds pretty incredible to me. Does this sound reasonable to anyone here or does this sounds like a bum deal? And is there anything else they should be checking instead of the carbs? I suggested ignition several times but they said they had already checked that...

They also presented me the option of going with a used 2006 115hp Yamaha for $6500 plus my motor as a $1,000 trade in, which also seems really low to me. Any thoughts on if that sounds reasonable as well would be great. Being new to this I'm really unsure if this sounds ok or if I'm getting ripped off. Thanks a TON for any info everyone.

By the way, is there any risk to running a bigger motor (115hp) than the 100 hp the Dory is rated for? Will that get you in trouble with the Coast Guard - or your insurance company???

Running (or getting ridden) rough in Seattle,
Beartrack

[Cutty Sark]

Didn't they just rebuild your carbs on their suggestion? I would want some sort of a credit if they charged you for that and are now telling you that you need whole new ones. The 115 sounds like agood deal, will it still be under warranty? How many hours are on it etc... I have heard from some fishing buds that three rivers is expensive for maintenance. Ad what you are going through does not sound fun. I would call some other shops to see what kind of deal you can get somewhere else, especially if you're going slightly used or new.

Good Luck
Sark

[ppriest]

I have no direct experience to use for comparison, but something you said struck me. You reported that the mechanics told you that, "to get it running smoothly they needed to adjust one of the carbs 2-1/2 turns and the others 5 turns, and they all ought to be about the same..."
The appropriate question to ask may be, "Can you get it to run smoothly under all conditions?"
If the answer is, "Yes," then the next question ought to be, "Can I do any damage running it this way?"
If the answer to that question is, "No," then it may be simply a matter of putting the boat on the water and running it.
This may not be a very satisfying or comforting scenario, but it may get you on the water which is really what you intended when this all began. It does sound as though another shop is in order. Good luck.

Paul Priest
Sequim

[thataway]

For what it is worth, Ed's Super Store in VA has the new 90 Yahama for $5300, and the 115 for $6000 in two stroke engines (may be a last year model)--and in the 4 stroke the 90 hp is $6500 and the 115 is $7300. Understand, that Ed's has a plus or minus reputation, and don't know if they ship motors or the cost of shipping. Then there will be the cost of rigging.

However, before coughed up 6 grand for a used motor I would check with other dealers. I would be disgusted with this outfit, and probably take my business else where--first they do a tune up, then rebuild the carbs, and now want to sell you new carbs or a new engine....I find this very hard to understand, unless that motor has been submerged, which I think is very unlikely.

The 4 stroke 115 weight is 402 lbs, and the 90 is 360 lbs.
The 2 stroke 115 weight is 358 lbs and the 90 is 261 lbs.

I am sure that your used motor is worth well more than $1000. Even a 1988 Johnson is listed for $1999--and you Yammie is a newer and probably better motor than that.

I have a 115 Yahama on an 18 foot bay boat, and it is a really great engine. I don't see where there would be a major problem on the C Dory--but it is considerably more weight aft than you have now and some would argue that for insurance purposes you are over powering your boat. But if I remember correctly that some of the boats have 115 hp on them with no problems. If you don't have trim tabs, you should put them on.

If it were me, I would get another opinion.

[dotnmarty]

Before you make any decisions, call these guys



Yamaha Motor Corporation, USA
1270 Chastain Road
Kennesaw, GA 30144

Sales, marketing and distribution of Outboard Motors.


Outboard Customer Relations
Exclusively for Outboards
(866) 894-1626

Let us know how you make out. Good luck.

[416rigby]

If it were me, I would find another Yamaha dealer. Plain and simple.
Sounds to me like these guys are just chasing their tails and there are a lot of Yamaha dealers out there.

[gljjr]

First things first. At this point I would do a compression test and a leak down test to see how healthy this engine is. Then and only then would I start to troubleshoot further. If the engine shows healthy (IE: all the cylinders have good compression and leak downs) then we can move on.

As you know the carburetors job is to meter the fuel it delivers to the engine so that it gets about a 16:1 air to fuel ratio. More air means the engine runs too lean and more fuel means too rich.

Popping back through the carbs can mean many things. Often it is due to being too lean. It can also be due to a valve being stuck open (not too likely on a 2 stroke but it does happen with reed valves). One other reason for this is having the ignition timing off.

So lets talk about the carb. The idle mixture screw only affects the motor up to about 1200 rpms. After that the fuel mixture is controlled by the main jet. If they are adjusting the carbs out 5 turns on the idle mixture screws then you either have a plugged up idle circuit (IE they did a lousy job rebuilding the carb!), OR you have a huge vacuum leak, OR the float is set wrong and the engine is fuel starved (IE they need to learn to rebuild carbs), OR the fuel pump is not providing enough fuel, OR you have a blown head gasket (this is why you need the leak down and compression check above).

If the problem is in fact the carbs (not really likely IMHO), my guess is that they dunked the jets in carb cleaner (very caustic stuff), rinsed them off with water and then blew it out with air. BUT the carb cleaner probably didn't completely clean the crud out of one or two of the jets. I don't think replacing the carbs is warranted. Either they did something wrong rebuilding them, or there is something else wrong!

If I were doing that job I would get the appropriate sized twist drill (a torch tip cleaner works in a pinch too) and put it in a pin vise and slowly/carefully clean out the jets. Then I would chase as much of the idle mixture passage as possible with a thin wire. Re-Assemble being very sure to check the float weight and height before hand.

Once we have the engine running it is time to adjust the carbs. With the engine at Idle and all carbs set rich on the idle mixture, I would start with 1 carb and turn the idle mixture screw IN until the engine stumbles, then turn it out a 1/4 turn. I would then do the same with the rest of the carbs. Finally I would hook up a vacuum gauge to each carb (all at the same time) and look at the readings. I would tweak the mixture to get the highest reading from each carb. Then I would make the readings the same for each carb by adjusting the idle speed screw for each carb. This is a painful process that can take a long time depending on how picky you are about getting it right! Once you have the engine purring at idle then you have to raise the RPMs and see how well it is synced off idle. IE: If you adjust the idle speed too high on one carb then when you crack the throttle that cylinder's vacuum will drop first as the butterfly is opening up sooner than the rest. For the best power you want them as close to the same as possible.

Please note that all my experience with multi carb setups is from 20+ years ago as an Auto Mechanic working on Solex carbs for VW's, Volvo's and various imports. Plus my various motorcycles and boats over the years.


Sorry for such a long post. But at this point more information is better for you. Good luck getting this fixed!

I'm actually surprised at your experience with 3 Rivers. I know a lot of people on Gamefishin that use them and swear by them.

[gljjr]

One other thing. In my 12 years as a mechanic the ONLY reason I had for replacing carbs was either a) the customer wanted a hopped up or different style carb, or b) the throttle shaft had too much play in the shaft bushing causing a huge vacuum leak, and c) something physically broke off the carb. Oh, I also replaced a carb and several other engine parts due to an engine fire melting the carb and intake. What a mess!

I find it very hard to believe that b or c is true with your carbs.

I also don't buy into the "Must replace all of them" statement.

[C-WEED]

The popping and backfiring is the obstruction in the low speed circuit. It smoothes out above 2000 rpm's as it begins to run on the larger high speed circuit.
I have the same engine. A 2000 model bought in 2003. Mine did the same thing as yours as it sat with water/crud/varnish in the fuel from the tank vents. I cleaned the carbs and ran a can of B12 chemtool ($2) thru them and no more popping and backfiring. Problem solved. That was in 2003. Been running fine ever since.

The screw adjustments being different to me indicate that the carbs are still obstructed.

Is it possible that salt water entered the fuel tanks and then sat in the carbs? If saltwater caused severe internal corrosion it might be a challenge. If this was the case upon carb removal this should have been pointed out to you. With the age of the engine and low hours I really can't understand why they can't get the carbs clean. They must not be doing a very good job of cleaning them when they have had them apart four times already? Their inability to make it run should not constitute carb replacement or another engine sale. Once the circuits are clean the adjusting screws will once again be within a half turn of each other.
What are they going to charge for THAT labor?

I would suggest you find another service center. After you get the 80 running like it should you can trade for a bigger engine if you want. That 80 should bring WAY more than a paltry $1000. Sounds like they set the hook and a tryin to reel ya in on both ends of the deal.

Good luck.

[Beartrack]

Gang - thanks IMMENSELY! I really appreciate the time and attention to detail in everyone's post. You've given me a bunch of ideas and a lot of great info. I'll start by running it a bunch this weekend at Sekui with some cleaner in there - I already have some Sea Foam in it but will get some B-12 for the second tank as I suspect I will likely need to fill up (it's getting very, very poor mileage right now... the other day a run straight from Mulketeo to Possession, trolling on the 8 HP 4-stroke Yamaha high-thrust, then coming back to about 8 or 9 gallons. So I'll run some B-12 through it for starters.

Also, regarding the question a few folks had, they apparently will credit the labor for the carb rebuild (but not the parts cost, which is I suppose reasonable) if I buy new carbs. Same credit if I buy the 2006 motor -and they did say that warranty is transferrable and the motor they say has 20 hours on it. If I go that route I'll ask for the former owners name to confirm the hours first.

On the comment about possible salt water in the carb - that's interesting! They mentioned yesterday that when they went to remove 2 of the carbs jets, they were "frozen in" and it took a great deal of effort to get them out and there was some white oxidation. If that's the case, is that oxidation likely something that can be removed /cleaned out somehow and if not, will that cause this type of issue? Supposedly they replaced the jets they said at one point... which also makes me wonder if the wrong jet size could have been installed... any thoughts?

On the leakdown, yes, they did do a leak down, let me know if this info helps... All cylinders were very, very close 3 to 4% leakdown, except 1, which was 25% - but said it clearly was on the exhaust side and thought there "was probably just some carbon stuck in there" and said it might just resolve itself this weekend when I get it out and run if for awhile. They did replace the intake gasket as well.

They also said each of the 4 times they taken it apart they'd chased all the circuits they could reach with every wire and small brush they could find of appropriate size and couldn't see anything obstructing, but said that you can't see all the passage ways.

For some reason I'm not 100% clear on, they are extremely convinced it is for sure not the ignition - said they'd tested it twice with some sort of ingition test tool/harness from Yamaha.

Definitely thanks on the pricing on the new Yamahas too; and $1000 trade-in seemed AWFULLY low to me too.

Again thanks for everyone's awesome posts and if any of the info above prods anyone with more thoughts, please feel free to respond!

Take care,
Beartrack (Scott)

[Dora~Jean]

Tough situation Scott, sorry about your troubles. All good information provided (and useful tips for all of us to apply if/when something like this occurs to any of us). Can this problem be duplicated in their test tank? If so, you'd think they'd be able to narrow it down to 1 or 2 carbs. But if they did a poor job cleaning the low end circuit on 1 or 2, maybe the same for all as well. I agree that the carbs are most likely serviceable (unless severely corroded internally) and should be cleanable. The cleaner will generally only work if the passages are 'partially' blocked. If totally blocked, it's been my experience they don't clear with cleaner and have to be physically run thru.

Not to belittle or make fun of the situation, but my mom once had a Kirby vacuum salesman come to the house and claim her old vacuum was essentially trash (5-7 yrs old). He offered to give her $10 for it if she bought a new one (and a deep discount on the new one after she wore him down). She needed another vacuum anyway for the adjoining house where her mother lived, so she bought the vacuum. Then she said I'd like to buy back my old vacuum for $10! She was convincing evidently, got her old vacuum for $10, it ran fine for the next 20 yrs I believe! Just a thought...

[oldgrowth]

Beartrack – just a thought. I am not a carb expert, but it seems to me, if the idle jets are adjusted way differently then when you run the engine and if the carbs clear up, the engine still will not run properly until the carbs are readjusted.
________
Dave

[gljjr]

Scott,

A leakdown of 25% is WAY too high compared to the rest. There should be less than 10% difference between cylinders. What about the compression test on it? Was the same cylinder low?

The white oxidation is typical of a carb that had water (or alcohol) in the fuel and sat for a period of time. Typically the cleaner bath will clean that stuff out pretty well. But I would have put extra effort in making sure the passages on those carbs were in really good shape before putting them back together.

It sounds like they have given you good information. If the motor runs well enough I think I would try to finish out the season and then replace it. The bad leakdown test is telling you that cylinder has a problem and that might be why you are seeing the poor transition from low speed to high. My guess is you have a stuck ring or a burned piston. Carbon won't cause a leakdown reading like this. It can cause a high compression reading but I've never seen/heard of it causing a cylinder to not seal.

There is every possiblity that if it is a stuck ring it clears itself up while running. I would run a slightly rich oil ratio if possible (this is a two stroke right?) to see if it might loosen up the ring.

Good luck at Sekiu! I wish I was going! I love it out there.

[C-WEED]

If you decide to go ahead and run it on the water with the B12 chemtool: Mix as directed. If you have a portable can for your kicker I would use that for starters. Running a bit thru your kicker will keep it running happy as well. If you can't get the boat on the water for awhile at least run the engine on the muffs for at least 20 minutes to get the B12 up into the carbs so it can be soaking for days until you get the boat in the water. If you run the engine off the CD tank it may take a LONG time to burn enough fuel at idle to get the B12 thru the hose, racor filter and into the carbs. Slowly increase the rpm's 12 - 1500 to get the cleaner in the low speed circuits. Pull up quickly and then close the choke enrichment to pull the cleaner thru that circuit as well.

When you do get the boat in the water and running. After a few minutes warm up. Operate the engine just above idle to really work the cleaner thru the low speed circuit. Cruise around at around 1500rpm. If the circuits are still obstructed the engine will make a muffled pop, pop and shpit, shpit sound. After awhile run the engine on up for a while and ensure it runs good at top RPM/speed then go back to the 1500 rpm routine. If the carbs aren't physically damaged this should clear it up in short order. As old growth pointed out, once the engine clears up the carbs will need re-adjusting. Check the compression when the motor runs better. I think it will be fine.

An old timer once explained that when you run the carbs dry of fuel you never get it all out. Even when you drain the float bowls with the drain screw by design most bowls have casting chambers for strength that retain fuel. The carbs are vented to the outside. So this fuel will eventually evaporate and leave residue behind. This is where the problem starts. He recommended leaving the fuel in the carbs. Especially if you run a fuel stabilizer additive. If you drain the fuel, you drain the additive. It is better to have both the additive and the fuel in the carbs. I have followed this method for years. I currently maintain over 20 engines on stuff around the house. Stuff like the generators, DR mower, rotor tillers, chain saw and power washer don't get used frequently. It is good to start them about every six months if you can. I have traveled in the military for years and when I return everything starts easily and runs fine. Just mix the additive in 5 gal cans. I use Stabil in everything all the time except the autos. I do those if I know I am leaving. If I leave tomorrow everything is treated until I return or until I use the item again. Give this method a try. It works.

Good luck

[Dora~Jean]

I'm a firm believer in Stabil also, it apparently has a cleaning agent in it that actually cleans out existing gunk with use. I use it all year round.

Maybe someone with more experience on low speed circuits can chime in, but on small motors I have pulled the needle valve screw and inserted the small nozzle tube of WD-40 (or carb cleaner) in there as deep as it would go and gave it several good shots. Repeated in about 1/2 hour. Then started and run as usual. It cleared up the problem most cases. Something that simple must have been tried at the dealer already though. But I don't think it gets into ALL of the low speed passages.