Brother has been having trouble with his motor since september.
motor is a 90hp 2 stroke Yamaha '02

Noticed a little bit of water in fuel filter / water seperator
It cuts in and out while accelerating after running for about 10-15 minutes in gear. After the boat planes out, it runs good...


It's been to two yamaha mechanics look at it already, had carb adjustments

any idea what the problem is or a shop that can actually fix it?

ask on www.iboats.com in the yamaha section, there's a guy rodbolt there.
eats those yamaha's for breakfast

Has it ever overheated? Could be headgasket.

if it's got those diaphram fuel pumps they go every two years or so.
can't get enough fuel and starts WHAH-whah-WHAH-whah,,, cutting out.
would make sense,it needs tons of fuel to get up on plane then not as much when your there so it smooths out?

Is he running a built in fuel tank? Could be crud in the fuel tank blocking some lines intermittently, it happened to a buddy of mine.

The Carb's may need cleaning and or rebuilding. The kits are around $30 per Carb. with around an hour per... labor. I know a guy in Qunicy who is great on them... PM me

Going to try a new fuel pump and fuel line this weekend. If that doesn't work he'll have the carbs rebuilt.

Fuel tanks are removable 6 gal tanks

Tried new fuel pump and blew out the fuel line.......still same problem. Going to it's 3rd mechanic tomorrow. :hs:

check for crap in the carbs, same thing happened to me with a yahmi. took 5 trips to mech to discover.

Do the carbs. I had a similair problem this past spring in my Yammi 200. The new ethanol based fuels is probably the source of all of our troubles.

I had a very similiar problem reoccurring on my outbourd. I have a 2003 200 HPDI. The problem was a dirty screen in the VST tank. Cleaned it and it ran fine.....Its a common problem on the HPDI's.

CLEAN AND REBUILD THE CARBS.....

Could this problem be be reduced by changining the RACOR filter more often? I noticed some sludge like crap and some water in there during a 100 hour oil change. I change the RACOR filter now with each engine oild change and have drained it from time to time just to make sure there is no buildbup, it only takes a minute. One questionable take of fuel and you are in for problems. It really does not take much gunk to screw up a carb or injector.

Drain fuel/water filter. Run engine directly off a 6gal. tank with fresh fuel thru the Racor fuel/water separator. Should'nt be any water in filter. If this solves problem then check your fuel tank. I have a 1989 C-Hawk w/90 hp Yami. Had gas/water in filter(Racor). Engine would sputter. Get it to plane and problem would smooth out until water built up again in filter. I changed filter, gas lines ,hose fittings, tweeked carbs.etc. No luck. Because my deck was a little spongy, I decided to rip it out. Upon inspection of the foamed in place 50gal tank, I discovered 3 holes in tank caused by corrosion. Emptied about 5gallons of water from tank. Foam was saturated with water and gas. Will be installing new plastic 36gal tank(no foam), a new stringer and new deck this spring. Hope this helps you. TK

How many hours on it?? Yamaha's love to get Carboned up! You can get some De-Carb and do it yourself.

Also try like stated above get a 6 gal gas can and run freash gas and see if that is it. If runs good you may have a hole in the line letting air in or a O ring on the conector's of the hose?

Could be out of time also?? I had a friend that had one and it was fine at idle and troll, but do try to go anymore then that, it will spit all over the place!

Good Luck!! Let us know what it was??

Well he got the engine back from the latest mechanic. He said the bar that links the three carbs was bent (How that would happen-who knows?) and the middle carb was sticky.
He gets the boat back and the spit & spudder is gone, but the plugs were still loading up after about 15 min.
Engine is now going back to same mech. to replace middle carb and rebuild the other two.


He tried the decarb and normally runs 6 gal tanks.

Do they still have points in there?? I had a old Johnson that would foul the plugs every trip, One set of points under the flywheel was bad, after that everything was great!!
Found this right after a carb rebuild that made no difference.:doh:

I'll bet that the rebuild/cleaning of the carbs will do it. The ethanol based fuels have really been messing with outboards lately. Please post the results!!

Well he got the engine back thurs of last week.....tried it out that fri and still had it running rough.......better than before but still rough for awhile when planing off. he had the one carb replaced, and the other two were cleaned. he also put in a new thermostat and plugs.

gets it back to him just today and he called back and said he flushed the fuel line & filter....ran off of his tank and said the fuel was the problem. he going to dump (the right way of course :angel: ) what little he had left in a 6 gal. tank and test it out again.

If that dosn't do it the mech. said me might call up yamaha to see if they'll spring for the repairs on the bent carb. He said his warranty had only expired a few weeks after the started happening.............:wall:

time to trade that puppy in

belive me....he's already though about trading it in......even upgrading to a 4 stroke.......but he'd get squat for a motor not running right



He actually got the mech to go on a ride with him on the boat, he said no it's not right......probably wouldn't show up on a dyno.

the same mech. tried new 'hotter' spark plugs and a new spark plug boot.....tested it this weekend....problem still there.
Back at it tomorrow :wall:


Yamaha regional rep. starting to get involved in things now.

well yamaha told the head mech at the shop that they want HIM to go for a test ride, not one of his guys. He said (to my bro. not yamaha) he wont go out untill it was about 60 degrees. We had that one day in feb. where it got to 58 he said no, a bit too windy. He called thurs. one or two weeks ago - just before it got warm. and said he was too busy with a boat show to go with him for the next three warm days! :realmad:

Mind you this should only take an hour of his time to do a short sea trial.

At this point he's writing a letter to yamaha to try to get something done before the season starts.

still?
man,,,, i'm glad i don't own a boat.:hidin:

My buddy had similar trouble with his carb yami. He has changed 4 out of 6 carbs by now due to clogging and degrading internal passages.
It is an older engine, but I think this problem is widespread.

Bummer about the dealer.