Gas additives

catsailor · Jun 10, 2009

I have a Yamaha 9.9 and a smaller Merc - similar issues.

RogerHM said:
How do they affect 4 stroke 9.9 engines? My Merc Big-Foot does not start consistantly. VERY frustrating!!! A call to Mercury headquarters, and speaking with a Tech Expert, I was told the ethonal and other gas impurities are the problem for many small 4 strokes. Especially when they may sit for several days between runnings.

Their solution... add Quick Clean to each tank of gas. Any experiences with this problem? Others have said to only use High Test gas. This is a manual-start motor. Would an electric start make any difference? Any comments AND advice will be much appreciated. Roger

Cleaning the carb helps. Small passages get clogged, and the needle can stick.

Enriching the idle mix a little helps, particularly if it is a pre-ethanol motor.

Keep a can of starting fluid on the boat. While it is not for regular use, a tiny tiny squirt can make a difference when needed.

Yet some motors are totally uneffected. I have a 18hp Nissan on another boat, and I can ignor it for months and it will start on the first pull. Don't know.

Tracy23758 · Jun 10, 2009

It has been my observation that the new 4strokes (I have a Yamaha 8hp) regardless of brand can be cold blooded creatures. Mine starts first or second pull every time but it takes some high idle time to warm up enough so it doesn't stall when put into gear. Kinda reminds me of all the Ford's I ever owned. LOL

Cpt. Jon · Jun 10, 2009

I lean toward Seafoam as my additive of choice but I only add it if the boat will be sitting for a couple of days or longer. If I think I will go through a fuill tank I don't bother. I am mainly worried about stabilizing the fuel and keeping the carbs clean. This is on my older 115HP 2-stroke outboard on my fishing boat, not a small, new, 4-stroke.

larryw · Jun 10, 2009

A previous boat had a Honda 7.5. I found a shot of carbuertor cleaner run through it helped, and when the float stuck, a tap on the bowl with a screwdriver handle freed it. Many 4-strokes benefit from a bit of Marvel Mystery oil in the fuel.

Manny · Jun 10, 2009

Try and run the engine out of fuel when leaving the boat for more than a few days. Per my Honda mechanic's suggestion (after a carb rebuild $$) at the end of my weekend I disconnect my fuel line from my tank and let the engine idle until it dies. Actually as I start getting close to the marina I pull the line and dock with the fuel line disconnected. Haven't had a problem since. I occasionally add some carb cleaner in the fuel just in case.

Manny

Cpt. Jon · Jun 10, 2009

Manny said:
Try and run the engine out of fuel when leaving the boat for more than a few days. Per my Honda mechanic's suggestion (after a carb rebuild $$) at the end of my weekend I disconnect my fuel line from my tank and let the engine idle until it dies. Actually as I start getting close to the marina I pull the line and dock with the fuel line disconnected. Haven't had a problem since. I occasionally add some carb cleaner in the fuel just in case.

Manny

I'm not a real engine guy (hence the sailboat perhaps), but there are those that argue against running an engine out of fuel due to the lack of lubricant. This may apply more to 2 strokes though.

RichH · Jun 10, 2009

Manny said:
Try and run the engine out of fuel when leaving the boat for more than a few days. Per my Honda mechanic's suggestion (after a carb rebuild $$) at the end of my weekend I disconnect my fuel line from my tank and let the engine idle until it dies. Actually as I start getting close to the marina I pull the line and dock with the fuel line disconnected. Haven't had a problem since. I occasionally add some carb cleaner in the fuel just in case.

Manny

What Manny states should be standard practice on ALL small gasoline engines to keep the carb. clean, and not fouled, etc.
Also be sure to use a fuel stabilizer in the tank .... or better, only use FRESH (less than 30 days old) gasoline.

larryw · Jun 11, 2009

Shouldn't take too many pulls if you have a bulb in the fuel line. Squeeze it till it's firm (don't go there) and the bowl should be full.

bffatcat · Jun 11, 2009

outboard starting problems

Ive got a 2008 4 stroke tohatsu

What the guys say is correct:

I have followed the steps below and never had any trouble. Per the dealer that sold me the motor

1. Dont use gas that is over 30 days old Any 30 day old gas gets poured into my cars gas
tank.

2. Put a capful of starbrite stabelizer in your fuel tank upon refilling

3. Always run the engine out of fuel when finished for the day This will avoid a gummed up
carburetor, especially if the boat is going to sit for several days

4. make sure your bulb is hard before starting.

5. Finally a couple of minutes warm up with the choke is normal before putting the engine in gear