Yamaha 4-stroke "Carburated Versions "opinions..

[Chad Halvorson]

Well we have the E-tec thread, so why not. Post your experiances.

Personally, I have a 2004 Lund Explorer SS with a 50 Horse Yamaha 4-stroke. Its been back to the shop 4 times, and never really ran right. Top speed of 29 mph on glass water, dies every time I try and holeshot, (staggers), same with when I load it on the trailer, I really have to ease those rpms up there to load it without it dying.

Im sure there is no longer any type of "warranty" so I havent bothered taking it back again this year, its worse than ever.

I have heard alot of people that have these are not happy. This is the version with 4 carbs, I belive they are now fuel injected?

[Can'tFishEnuf]

I have that same motor, 50hp - 4 stroke with the carbs. It can sometimes be hard to start if I haven't been out for a couple weeks, but other than that it runs pretty well. When I first got it had the wrong prop on it and I had no hole shot, stalled, could not get on plane. After getting the right prop it's been fine. Get about 30-35 mph depending on the load in a 16ft boat.

[Corey Bechtold]

Yamaha is aware of some of the issues with the 4-stroke carb. If you call the company direct and explain your issues I'm sure they will take care of you.

I had a few of the same concerns your exact motor and they found the problem. Unfortunately a lot of the dealers don't know how to correctly fix the problems. When they sink and link your motor they have a certain order that they need to do the procedure. This is absolutely critical in getting the best performance out of your motor.

Let them know about your problem and let us know what you find out.

Good luck,

Corey Bechtold

[caseymcq]

I have a 75 hp Yammy that is EFI and I love it. After I got it out of storage this spring I hit the key and it fired up right away. I can get plenty of speed out of it on Alumacraft Navigator 175. It is extremely quiet. It runs smoother than any motor I have ever seen. It trolls down really nice. I can't say enough good about it.

[icecold]

Any 4 stroke be it merc or yami with efi is a night and day difference than the carburated ones, the efi makes them start and run like a 4 stroke should, go efi

[mahannah]

Well for what its worth, I have a 2003 Yamaha F60 that is carburated. It runs like a champ.

As others mentioned it can be a little hard/slow to start when cold. Here are some things I do that seem to make all the difference. Note I have never had ANY problems with the motor running once it is warm. Only a little cold blooded when starting.

-Run seafoam in the gas. The jets in these carbs are very small and can gum up easily, especially if you use the oxygenated gas found in MN which goes stale very quickly.

-Always pump up the gas bulb until hard. I have found that tilting the engine to trailer seems to empty the carbs. If you remember to pump the bulb good after trailering this helps a great deal when starting for the first time.

-When I fish in the fall and it is very cold out, I will twist the throttle twice with the key in the ON position before I turn it over. This seems to prime the engine and it starts immediately as opposed to several tries.

[TSCTSC]

How do I know which Yamaha 4 strokes are EFI and not carburetted?

[Northlander]

I have a 115 Yamaha 4 stroke and it has been a very good motor for me. Its on a 1700 Lund Explorer and it gets the boat on plane well and tops out at 43mph.

1st time out this year I hit the key and she fired right up.

I have nothing bad to say about it except its a mess to change the oil with the plug being above the prop about 6 inches.

[Chad Halvorson]

Quote:

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How do I know which Yamaha 4 strokes are EFI and not carburetted?

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I believe they came EFI in 2004 or 2005. My boat is technically a 2004, but I think the motor is 2003?

[caseymcq]

Quote:

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How do I know which Yamaha 4 strokes are EFI and not carburetted?

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It will say "Eletronic Fuel Injection" in red letters on the back of the cover.

[TSCTSC]

OK....I am not so good with engines. But I know our cars are now 4 stroke and EFI. But what is a carb 4 stroke?? How and why is it different?

[Chad Halvorson]

No cars today come carburated, I think that all ended in about 1986 or so. Fuel is injected right into a rail or right into the combustion chamber with "EFI". So, technically all cars with a carb are 4-stoke Carb'd. Maybe a few before then had efi but most were carburated.

[wplatehunter]

I have a 100hp 4 stroke yamaha and love it. It can be a little cold blooded, but I have not hand any problems knock on wood other than bad gas.

[Guest]

Chad,

Are you running Ring free or Sea Foam in your gas?

It sounds like your carbs are dirty or gummy.

Yamaha carbed 4 strokes gum up if you don't use one of these gas additives.

[marine_man]

Quote:

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Unfortunately a lot of the dealers don't know how to correctly fix the problems. When they sink and link your motor they have a certain order that they need to do the procedure. This is absolutely critical in getting the best performance out of your motor.

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This is 100% correct... the carbed 4-stroke motors are extremely touchy on this and unless you have a highly calibrated ear / funny bone it is hard to do without the vacuum gauge that shows the vacuum on all 4 carbs at once...

marine_man

[ScottND]

Seeing the prices they get now for service ($119 an hour at one place in Fargo ) makes me gratefull I have all the years of experience and tools I've aquired. I've got a 2001, 80 hp, carbed, 4 stroke Yammy and I can tell it needs to be synced. I'll just pull the mercury (or adjustable multible air) gauge off the wall and do it.

You are right...there is a certain order used to sync. I've seen 4 cylinder 4 strokes where you sync all cylinders individually and others where you need to sync certain pairs and then sync the pairs together. Syncing multi's with a single manometer will only get you "in the ball park" but for "right on" it can't be done with out a multi gauge.

Hmmmm, sounds kinda fun . Might have to do that tonight after work and then install my hydraulic steering so I can let go of the steering wheel without the motor torque and weight doing the steering and trying to throw me out of the boat.

Right now I'm roughly idling @ 600 - 700 RPM at about 2.6 MPH. My goal will be 400 - 500 and hopefully 1.8 - 2.2 mph.

[DanS]

Chad,

I have a 2004 Lund Explorer with a 60 horse Yamaha 4-stroke on it and I have had the same problems. If I try to pull the kids skiing the motor dies. Loading on the trailor the motor dies. Its cold blooded, hard starting and has dead spots in the acceleration. The top end around 31 mph. I have always ran ring free and used premium gasoline (no ethanol)and still had the problems. I've had the motor back to the dealer 5 times now. The last time was late last fall and the dealer had a Yamaha factory rep work on the motor. I did'nt have a chance to check it out much after the rep worked on it but he did water tested it and thought it ran well after some carb work.

[minnesotamusky]

I have a 2000 Yamaha 50hp 4 Stroke. I've had all the same problems as everyone else here. Starting to think I should trade it in for something different. My lastest problem is the trim/tilt. When I raise it, it will slowly fall back down. It usually take about 15-20 minutes for it to go all the way back down. Also when I am going across the lake it starts to drop, then I have to keep adjusting the trim/tilt up. Took it in and the guy said that there are two valves that could be leaking. He said that it would be about $400 to replace these valves. There are no visiable signs of anything leaking. Any ideas on what would be causing this???????

[TSCTSC]

So it seems that the Yammy 4 strokes are not as bullet proof as they are made out to be??

In any case, I used to have a 90HP 2 stroke. It used to have a rough idle problem and a "lean sneeze" issue. Finally fixed by dealer after a few visits. The final fix turned out to be a screw that they needed to adjust. Cost of that was 38 USD. But I had spend about 100-200 USD before that. Imagine that.

I also have the trim and tilt problem in that motor. It was intermittent and the dealer could not replicate it. I have spoken to some people and the possibilities are in view of no obvious leaks :

1. Sensor problem - but if your motor is physically coming down, then that is not likely

2. Some check valve problem - someone said that occasionally, the valve does not work well and it will happen

That is all I have on the above. Hope that it helps somewhat and please keep us posted. Thanks.

[SuddenlySummer]

I'm going on my fourth season on my 75hp/carbs. Never had a problem until the end of last year. I took it in for a tune up and it's still great. I've pulled tubes and wake boards for three summers w/o an issue. She is getting a bit cold blooded but I just take an extra minute at the dock to let her warm up.

I'd own another one.

[markkstanley]

No problems with my 80hp 4 stroke tiller. It cranks up all winter on Pool 4. And I got it down to 1.8mph at idle. Did have hydraulic lift problem mentioned earlier when I first got it. R and R Marine fixed it no problem after that.

[leekie]

2004 Yamaha Four Stroke EFI 150 on a 1800 Pro V. 50 mph and this thing never misses a beat. Troll down to 2.5 without a sock and never loads up. Great motor!

[marine_man]

Lonewolf -

The only quick thing is to check is whether the manual bypass valve screw is tight - on the motor mounting bracket (where the motor mounts to your transom) on either the left or right side toward the bottom of the mounting bracket there should be a slot cut in the mounting bracket with a big flat screw head on it - put a flat screw driver on that bolt and make sure it's tight. Don't reef on it... just make sure it's tight.

If it's not that I can't help you too much more.. sounds like internal leakage in the T & T.

marine_man

[TiredOfWorking]

I have a 2003 90HP Yamaha 4 stroke on a 2003 Lund 1675 Explorer. The motor has always run flawlessly. It started on the first turn of the key this spring. When I start it cold, I always let it warm up at idle for a couple minutes before I take off per the manual.

[Corey Bechtold]

Lonewolf, there is a screw on the backside of your motor that might need to be tightened a bit. I had the same problem and it was just the screw. It has a little picture of the motor and a directional arrow. This is there in case there is a problem with raising or lowering your motor. If you loostened the screw you would be able to manually raise or lower it. Give the screw a snug up and it might take care of your little proble.

Let us know if that fixes it.

Later,

Corey Bechtold