Yamaha 80 feedback

[trpsurf]

C-brat gurus. I am very near the purchase of my first boat- a 2003 22' Cruiser. Needless to say we are thrilled about the potential adventures ahead and cruising/ fishing/ diving in and around the channel islands here in Southern California.

The boat appears to be in fantastic shape and I have a sea trial and survey scheduled soon to go over every nook and cranny, as well as a motor diagnostic.

Given that the boat has a single outboard, a 2003 Yamaha 80 with 524 hours, the relative "health" of this motor is critical.

I have done an extensive search on this site for information on this engine and really only come across some horror stories about Carbs, these motors lasting 800 hours, and other challenges. I am wondering if any folks here have had positive experiences with this model of motor.

I would value any insight, positive or negative, on this engine model- things to look for, watch out for, worry about, etc.

Thanks,
Tim

[dutch123]

I have a Yamaha 80 carb as well and have been happy with it. As long as you are doing your regular services and maintenance and the carbs are tuned for the proper elevation I don't think you will have a problem.
.Obviously you will be getting as much info as possible on the history of this motor as the previous owner should be able to tell you what kind of maintenance and or repairs this motor has gone through. A well maintained motor with over 500 hrs should still have lots of life in it. From my experience (zero timing) all your engine maintenance issues on a new to you engine is a good way to assure your on track for a long engine life. You may want to replace your impeller right away as well just to be sure. Good luck, just think soon you will be the proud owner of a 22 foot Cdory!

[Sea Wolf]

trpsurf-

For general clarification for those just following this thread:

Is the Yamaha 80 is a 2-stroke engine or a four-stroke?

I know they've been making the 75 & 90 hp four strokes for quite a while, and in 2005 added EFI to them.

At sometime earlier, they offered a 100 hp 4-stroke, and the de-tuned version of that may have been an 80, which may be what you have if it's a four.

Joe.

[Will-C]

We cruise with a friend who has a 22' Cruiser with a Yamaha 80. Other than carborator problems from the boat sitting a long time and the carborators needing to be cleaned up and rebuilt at the time he purchased its been a good motor. His is is faster than a friends simalar boat that is powered by a Honda 90. As with any carborated motor running Blue Stabil or an ethanol additive of your choice along with Yamaha ring free goes along way to keeping this motors running well along with normal oil and filter changes. Yamaha these days recomends a 10 micron gas filter. I would consider running the carborators dry and draining the float bowls if it is going to sit more than a month at a time. It might make sense for the local Yamaha dealer to check out the motor before you buy.
D.D.

[trpsurf]

Thank you for the quick responses.

For clarification it is a 2003 Yamaha four stroke. I believe it is carborated.

[416rigby]

We have a 2001 Yami 80 with about 540 hours and we're the second owners. As with any carb engine, especially, the fuel system is something you have to be vigilant about. We just had the carbs rebuilt and my mech strongly recommends draining the float bowls if the engine will not be run for any length of time. It's easy to do. I've taken to doing that now if I won't use the boat for a couple of weeks or more. Ethanol gas sucks.

If you have the motor plumbed with a quick disconnect you could always pull it and run it til it quits, which is what we do with our kicker.

Blue Sta-Bil is your friend! Use it! We also have a spin on filter/water seperator.

Having an outboard guy peek at the engine is not a bad idea and may be worth the money. At least have the compression checked, especially if the boat has been sitting a while.

Welcome to the fold,
Rick

[jennykatz]

The yamaha 80 and 100 hp are the same engines as the mercury 75 and 90 hp a 1.6 litre carburated engine ..mercury and yamaha used to have a marketing agreement from 40 hp down was a yamaha from 50 up a merc. these engines were called mariner's . mercury got pissed when yamaha was bringing in motors below their cost ? these are all 4 stroke 4 cylinder engines .Year ago the mfg. could say their engines were +or - 10% now I believe it's more like 5%.

mercury used to use a yamaha block for their 50-60-75-90-115 and their 225hp engines Now mercury uses a 1.7 for 75 through 200hp verado engines The 75 -115 is non supercharged the 135-200 is . Now mercury is building a new 3 litre single overhead block 150 hp engine to go against yamaha 2.7 litre 150 hp.

[potter water]

A little cautionary tail about the Yamaha 80 if it is a de-tuned motor such as was used in my 90 hp merc. Check to see where the carb vent line gets its air from. If it is straight out the bottom of the engine case, be cautious in waves that may be coming from the aft end of your boat, or when you are backing with waves.

Here's my story.

I had a 2000 model year merc 90 (Japanese head). on a mini-houseboat. It did have some quirks. The carburetor vent hoses all came together and into a single hose that vented out the bottom of the lower motor case to outside air. If I ran the motor in reverse against any wave activity, the water would get sucked into the carb vent hole, and would kill the engine. And it took a scary 3 or 4 minutes to get started again. Once I had forward momentum that was never an issue, but pulling backwards off a beach or out of a dock with any incoming waves was always problematic. I can't for the life of me figure why the Japanese or the Merc people put that carb vent hole where it was. The motor was very heavy...a BIG motor for the 90 hp it provided. But, aside from the vent issue, it never failed over about 5 summers of boating.

So, if the Yamy version of my merc has that vent location, be careful.

Just sayin'...

[Dora~Jean]

I believe I have your exact motor on my 25 CDory. I have twin Yamaha F80's. I've had nothing but perfect performance for going on 9 yrs now. I don't drain my carbs after use, but I do you StaBil religiously. I'm considering draining them in the future just as a precaution since I don't get out as regularly as I have before.

These engines should last into the 1000's of hours if properly maintained and not abused. As recommended, renew your water impeller. Also might have a pressure check done on the lower end seals, most outboard shops can do it. It is good insurance against water intrusion into the differential. I've replaced all the seals on both engines about 3 yrs ago, no problems.

Other items you or the mechanic should check are the valve clearances and carb synchronization. I check these every 100 or so hours.

And welcome to the family!

[thataway]

I owned a boat with a 2003 Yamaha 115 (fuel injected) and it was a great engine--I sold it with over 600 hours, and it is still running fine with over 1000 hours according to the buyer. The hours on your motor are not the issue--how it was cared for is. It should have been washed out with fresh water after each use.

[Matt Gurnsey]

While Merc and Yamaha were working together during that time, Mercury would use their own carbs and ignition components (as well as lower units) on the Yamaha block.

So problems on a Merc might not be found on a Yamaha, as they were not rebadged engines like the Johnson sourced Suzukis or current Mercury Tohatsus.

[jennykatz]

Matt I forgot to say that that it was merc lower units and ignition systems . What yamaha got was mercs proprietery paint system and better corrosion protection .Now I think Yamaha is as good as the mercury protection for corrosion

[C-WEED]

I was the third owner of my 2000 boat/80 H.P. and it also served time as a demo boat for Three Rivers Marine at some point. The engine is a detuned 100. That is why the cowling looks huge.

Mine came with carbs that had began to get pluged up from lack of use, fresh fuel and fuel conditioner from previous owners. The engine is tuned to run very lean to meet emmisions. They can be tricky to get started the first cold start of the day. Only two of the four carbs have start inrichment. The tell tale signs of gummed up carbs are hard to start. Rough idle when cold, not firing on all cylinders (engine shakes) until warm, popping and sputtering back thru the carbs, longer warm up, rough running at about 2500 rpm when it changes to run from idle circuit to main fuel circuit and not accelerating smoothly up to full rpm under way.
The manual recommends idle for two minutes after cold start.

As others have stated carb issues are generally avoided by using fresh fuel, fuel conditioner, draining carb bowls when not used for awhile. And use non-ethanol fuel if possible. If the carbs are clean the engine should light right off and idle smooth.

Parts are readily available and the engine is of basic design and easy to maintain and repair. The only failure I have had is the plastic tab that pushes the sensor for the engine trim gauge cracked. I repaired it with a piece of safety wire. (Pic of repair in album) The carbs are easily removed for cleaning if needed. You can purchase an inexpensive ultrasonic cleaner for cleaning the carbs. This device uses vibration and water with a dab of dishwashing liquid. (it can clean many things including jewelry) It creates micro-explosions of the water to clean the smallest of passageways (both air and fuel) in the carbs in just a few minutes. The carbs must be disassembled one at a time and dropped in the container. If you can clean these yourself it will save you huge money. Manuals are available and anyone here can help with any questions. I have some pictures of the carbs off if you need to see whats involved.

The only problem I am aware of and it affects the 115 as well. The drive shaft runs down from the power head and enters the lower gear case. There is a seal at this point where the shaft enters the lower gearcase. If you look in the gap (between mid section and lower case) you can see the shift linkage connection and the shaft. This seal (just below the gap)hardens over time. It will produce a loud squeal usually when the engine is operated at 1500 to 2500 RPM. This happens to be where the CD putts along at 6 knots. Squirt some oil or white grease in the gap and let it run down the shaft to the seal and it should quiet down.

Yamaha recommends using a product called "ring free" labeled by Yamaha. This is to prevent carbon from building up on the rings, combustion chambers and the backsides of the valves. I assumed the sta-bil fuel additive would suffice. Wrong... When I removed the carbs you can look in on the backside of the valves. I was shocked/amazed at the carbon build-up at 230 hrs. I spend a lot of time idling along so this probably compounded the problem. I now use ring-free. It seems pricy when you buy it but the dose required isn't much. These engines are really high performance and the additive helps with todays crummy fuels. Ethanol free fuel will give much better performance, fuel mileage and less carb issues.

Enjoy your new boat!

[Wefings]

The test you want to do on a 4 stroke to check for wear is a leak down test . It measures how long the cylinder will hold compression and tells a better story than a simple compression test . Ethanol and those carbs are not a great combination ,but can work with vigilant care.
Marc