1997 2 Stroke 40 hp Help!

cflohr

Cadet
Joined
Sep 5, 2007
Messages
6
Hi all...new to the forum. Glad I ran across it.

I bought a 16 foot Carolina Skiff last week. The boat came with a '97 40 hp 2 stroke Yamaha. I ran it on the water before buying, and got out in it for the first time this past Saturday. Everything seemed great. Had a compression check and everything checked out.

Was heading to the water this evening, and noticed that I had fuel on the floor of my boat, and realized that I had closed the vents, the temps today reached 97 and it looked like the pressure built up in my tanks and spewed some fuel. Anyway, was running on the water this eveing and everything seemed fine. ABout 30 mins into it the engine started skipping or sputtering when running at or near full throttle. It seemed fine when running at half or low speeds. The problem came and went, and we headed back to the ramp. Killed the motor, went to get the truck and thought that I would try it one more time before loading up. Started the motor, put it in reverse and a nice puff of smoke came out of the motor. I engaged in forward and the boat seemed to run fine. While I just ran for a few minutes, the problem seemed to have disappeared.

Is it possible that the pressure that built up in the tanks caused some kind of problem with the mixture? Could I have had air in my lines or motor? Was I possibly buring too much oil? Thanks for any thoughts or advise. Sorry for the long first post.
 

cflohr

Cadet
Joined
Sep 5, 2007
Messages
6
Re: 1997 2 Stroke 40 hp Help!

No thoughts? Come on guys! Help a novice out.
 

BruceAML

Petty Officer 1st Class
Joined
Feb 26, 2007
Messages
371
Re: 1997 2 Stroke 40 hp Help!

Do you have a spare tank and fuel hose that you can substitute? Are you using a plastic or metal tank?
 

cflohr

Cadet
Joined
Sep 5, 2007
Messages
6
Re: 1997 2 Stroke 40 hp Help!

Do you have a spare tank and fuel hose that you can substitute? Are you using a plastic or metal tank?

I do have a spare tank, not a spare fuel hose. I am using plastic tanks?
 

BruceAML

Petty Officer 1st Class
Joined
Feb 26, 2007
Messages
371
Re: 1997 2 Stroke 40 hp Help!

Possible vapor lock, stale fuel. I would not be overly concerned. What fuel/oil ratio are you using? What kind of oil?
 

cflohr

Cadet
Joined
Sep 5, 2007
Messages
6
Re: 1997 2 Stroke 40 hp Help!

Possible vapor lock, stale fuel. I would not be overly concerned. What fuel/oil ratio are you using? What kind of oil?

Using 50:1, or 4 oz. per gallon. Do not reall the oil, Bass Pro Shops Special. Is there a better oil to be using? Thanks!
 

BruceAML

Petty Officer 1st Class
Joined
Feb 26, 2007
Messages
371
Re: 1997 2 Stroke 40 hp Help!

Yamalube 2-M oil. Oil is cheaper than engines!
 
Top