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**TownsendsFJR1300** · 10-17-2014, 04:37 PM

How old is the fuel in the system?

If its over a month old, have you used any fuel stabilizer in it? Ethonol fuel will go bad in as quickly as a month.

Have you found any crap in the under cowl, Yamaha fuel filter? I've had one line(marine yet) where the insides of the line started falling apart. Luckily the under cowl filter caught it and I saw it before it got any farther..

If the engine is carbed, you can start by pulling float bowl drain plugs and catching what comes out. Your looking for any debris, yellow varnish, fuel line paricles, etc.. I use a small tuna fish can to catch what comes out. Any cloudyness of the fuel or water separation indicates water in the fuel (ethonol attacts water)

Yamaha makes an EXCELLENT fuel system cleaner called "Ring Free". Depending how clogged the carbs are, the RingFree may help.

Re draining the tank, you can drain a good part of it just unhooking the fuel line to the engine, running a line into a tank (or several), prime the bulb and let it siphon into an auxilary tank. To fully drain, your looking at probably pulling the tank, flip, etc.

I would be looking/ smelling the fuel closely, especially what comes out of the carbs. Stale fuel is very distinctive(obviously be very careful doing this) and you can compare it next to a little bit of fresh fuel...

**IguanaBait** · 10-17-2014, 05:03 PM

I just tried to siphon the gas but the clear tubing only goes so far down the tank until it hits a wall and won't go any further. Is there another way to siphon gas? Also can you take apart the carburetors while there is still gas in the tank or will it all come gushing out?

I have an image I want to upload but I can't figure out how to.

I forgot to mention that the fuel is definitely ethanol and has definitely been sitting in the tank for well over a month.

**robert graham** · 10-17-2014, 05:09 PM

Your carbs probably need cleaning, check fuel visual and by smell before draining system, after this install a fuel/water separator type canister filter on your transom, use Stabil fuel stabilizer all the time....more or less depending on the amount of time motor/fuel will be laid up.....

**TownsendsFJR1300** · 10-17-2014, 06:37 PM

Originally posted by IguanaBait View Post

I just tried to siphon the gas but the clear tubing only goes so far down the tank until it hits a wall and won't go any further. Is there another way to siphon gas? The fuel line that goes to your primer bulb, just hook a hose to the primer bulb (instead of going to the engine), give it a prime and let it empty..Also can you take apart the carburetors while there is still gas in the tank or will it all come gushing out? The only fuel that will come out is whats in the carbs and lines ABOVE the carbs(very little). Stick a rag/towel underneath to catch any excess (and disconnect the battery before doing so)

I have an image I want to upload but I can't figure out how to. Down below, (this page) there's a section for "Manage attachements". Open that, find your image and upload..

I forgot to mention that the fuel is definitely ethanol and has definitely been sitting in the tank for well over a month.

. I would inspect whats in the float bowls, drain out what fuel you can out. [B] How big a PIA is it to pull the tank and flip upside down, maybe blow out with an aircompressor?
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There's usually a main and idle jet. You can usually get by with just removing those jets, and cleaning them, making sure you can see light thru them. Carb cleaner and air alone doesn't cut it. Some jets have horizontal orifices that can't be seen unless the jet is out.

*As a side note, I used to use ethonol fuel and found water building up in my 60 gallon built in tank. (visable from the VST drain). The boat is a 1997, tank NEVER removed, NEVER drained... I starting using Non-ethonol fuel, RingFree and a product called K100;

Video;
Demonstration Videos | Kinetic Fuel Treatment

http://k-100.com/

Between the use of the K100, non-ethonol fuel (it did take some time), there is no more moisture visable when I check. The water may still be there however it keeps it in suspension and eventually burns it off. The fuel in the boat is close to a year old however it smells/looks brand new and is clear/NO separation. (I do NOT have any affiliation with K100). I do have a fuel water separtor as well, no water either.

Here's a link for your carbs; http://www.boats.net/parts/search/Ya...201/parts.html

**99yam40** · 10-17-2014, 07:50 PM

Originally posted by IguanaBait View Post

So I'm having an issue with my 2003 75HP Fourstroke Yamaha. It won't start now and I can't figure it out. I just went to a marina today to buy recreational fuel and I talked to a lady there, she said that the engine is acting up like that because I used ethanol fuel. She also said that I would have to rebuild the carburetors, replace the fuel lines, and have the gas tank completely cleaned out. Is it really this serious. Im curious what the correct way to completely siphon and boat of gas is. Here is a link for the noise that my engine was making two weeks ago. Please leave URL's that can help me out or feel free to leave your opinion.

https://www.youtube.com/watch?v=sJ6lDwJBR2s

You really need to have some knowledgeable person to check the motor out for you preferably a trained Yamaha tech.

people can give you all sorts of advice on your motor without doing any type of testing or inspections of the systems , some can be correct and others not so much.

Will not hurt to do all of this if it is done correctly and does not mess up other things, but if the fuel, tank, and fuel lines do not need the attention then it will be waste of your time and money.

Always test and inspect things to find out what the problem is before attacking it.

Carbs sound like they need attention from the lean sneezing in video, but are the lines bad?
Is the fuel bad?
does the tank need to be cleaned out?
Depends on what you find in the filters, pumps, and lines and the carb bowls.
The fuel can be looked at, smelled, or tested to see if it has gone bad.

Lines can be inspected too.

From what you have written so far I can say there is a very good possibility you do not have the equipment or knowledge to sync the carbs on a 4 stroke even if you clean them out properly

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