Regarding Yamaha80's and rusted fuel sending units

[djnward]

Well fellow C Dory owners. I’m new to large, fuel injected outboards and have learned a few things that I thought I'd pass on. Hopefully it will help someone as much as this site has helped me.
I recently purchased “Cappie”, a 1999 C Dory with a 2001 Yamaha 80HP. There were two problems…one I caught while purchasing it (and which the previous owner made good) and another which is evidently a common problem with Yamahas. BOTH had the SAME SYMPTOMS.
Firstly, the two fuel tank sending units were replaced in 2001 when the boat was converted from a two stroke. By the time I bought the boat, they were considerably rusted and had seriously contaminated the two fuel tanks; one much worse than the other. Small red particles could be seen in the fuel which lead to blocked jets. The previous owner seemed maticulomaticulous taken very good care of the boat but had no idea of the contamination.With one tank considerably worse than the other, I'm lead to believe that either that sending unit was faulty or that the tank with the worse unit was empty more of the time (exposing it to the air). Either way, the replacements are just metal also…and not stainless. I’m surprised they aren’t plastic. Actually I haven’t researched them extensively so maybe some of them are. I went with what was on hand for now.
The other clogged fuel problem regards the Yamaha 80. My mechanic (who has worked on Yamaha’s for the 25 years I’ve known him (I figured he’d be a good choice!) says that it’s common that the needles into the ventury get stuck by burrs on the seats. He said he had learned this the hard way on another boat a while back. Particularly when the motor is trailed, the float can bounce and jamb them into the seat causing them to stick…..today two cylindars were blocked. Socylindersrized air shot into the fuel line (or if your lucky just pumping the fuel bulb very hard) will unseat them but they must be removed and the venturies reamed. He says if the boat is left in the water often times the problem will not reveal itself until it's well along. He recommends running the engine for 1 – 2 mins with the fuel turned off before loading it on a trailer to keep the float well below the needles so they won't collide. He is presently reaming my seats.
Anyone else have this problem? Anyway, to all Yamaha owners out there, keep this in mind incase your Yamaha isn’t “running on all cylinders” so to speak....... and literally.
Dick

[416rigby]

Good to have you aboard, Dick. Thanks for the info, and hope you get your issues resolved soon so you can get out on the water.

Never heard of that carburator issue before. We have a 2001 F80 on Foggy Dew and she runs great. I do pump the ball until it is very firm, though.

Do you have the see-through gas tanks or the greenish ones? If you can see the fuel level, I'd just forget about the sending units altogether. Took me a bit of getting used to not having a gas gauge in the CD, but now it's just ops normal.

Rick

[djnward]

Hi Rick
Yup, I've got clear-ish tanks. It's hard to see the level but when the lights right it's visible. Thought I'd see how useful the senders are and then decide. Foggy Dew looks great. I had earmarked your sunbrella curtains as a nice simple solution to the privacy issue.
Smooth Sailing
Dick

[C-WEED]

My 80 H.P. has always started and run rouff when it is cold. I assumed this was because only two of the four carbs has the cold start enrichment valve installed. Thus running better on the two cylinders with the enrichment valves than the two without until it warms up. I am sure only using two valves instead of four is to meet emissions. I'll keep an eye on the starts and look for sticky float needles.

[Dora~Jean]

The only time my 2003 Yami 80's (carb) have run rough at startup was when I had my son pump the primer bulbs for his first time and he stopped when he felt backpressure, he now does it right by pumping till quite firm. All 4 carbs must get fuel to their float bowls. I also had to replace both primer bulbs when they were about a year old, the ends started leaking fuel and couldn't get much pressure out of them (internal valves). On mine, all 4 carbs are identical and all have the enrichment valve and circuit.

[djnward]

Chris: what and where are the enrichment valves? I'm assuming they act like a choke?

Rick and Steve: I admit to not having taken the pressure in the primer bulbs seriously enough. I'll remember that in the future. The previous owner mentioned pumping them a little more if needed. I figured the bulb just picked up the slack in the line, not topped off the carburators.

Thanks
Dick