f115 hot start issue

[egstasea]

I have a 2005 115 hp mercury fourstroke. Knowing I have the same power head, I have read most of Rodolts posts regarding the f115 hot restart issue/excessively rich.

When the engine won't restart after a hard run, Rodbolt suggests starting with the throttle advanced. It always works. I also have found if I cut the engine at 2000 rpm, I get get reliable hot restarts. I just don't want my wife and kids to have to do this.

Rodbolt has diagnosed this on other sites as needing a vapor shut off valve and recovery tank. I have never been able to find that kit.
Can I just disconnect the VST vent to the air box? Is it dangerous to vent into the cowling? Is there a charcoal canister kit for my engine?

[boscoe99]

I would not vent the VST inside the cowling. I suspect you know why.

Why not just extend the hose and vent it overboard?

There is no retrofit modification that I am aware of that provides for shut off valves and a charcoal canister kit for the F115TXR models. For the F150 yes. For the F115 no.

But having said all of this, if the motor ran well for the past 10 years but now does not run well, I am thinking that a vapor recovery kit might not be needed. Perhaps something simply needs to be replaced for the motor to run as it once did.

[rodbolt17]

could be as simple as the fuel blend.

[boscoe99]

Yep, it is extremely warm here in jawja. If someone had a dose of winter blend fuel and tried to use it in our current climate conditions that could be a problem.

[egstasea]

This is a symptom that was happening last summer. I only use 91 non ethanol. Is there a vapor shutoff kit for this engine?

[boscoe99]

This is a symptom that was happening last summer. I only use 91 non ethanol. Is there a vapor shutoff kit for this engine?

Not from Yamaha. Don't think there has ever been a need for one.

Maybe Mercury Marine offers one.

[egstasea]

fixed

I know this is old, but I always like to post a resolution to a problem. What I did find out is the 2005 vintage Mercury does have the VST vented to atmosphere, so that was not the problem. The engine did however need the throttle synchronized with the four port vacuum gauge and the TPS adjusted. I did not have those tools and had a good mercury shop do it.

Runs and starts great now under all conditions.

As a bonus I found out my 10 year old motor only has 230 hours on it when the hooked it up to the YDS computer.

[boscoe99]

Thanks for the feed back.

Glad you found the problem.