vapor lock problem

[tinathetige]

2000 Tige 20i
No problems for years, then last few summers began having vapor lock issues. Problem occurs without warning. Engine runs fine, several hours, no problem, then alarm will sound and engine dies. Finally took to mechanic for help. Mechanic replaced one way valves on fuel tank and on vent tube. Boat ran great all day. No problems. Next day, after running for awhile, then sitting idle for an hour or more, won't start. Alarm sounds, engine backfires. Dead in the water. Any suggestions???

[TeamAllen]

Welcome to the site and sorry to hear about your issue. It seems to be caused by the increased ethanol in the fuel.
There are quite a few previous threads about the topic. I'll dig up a few.
There are a few remedies you can do to help it form occurring, but the end result is you should add a second fuel pump closer to the fuel tank to push the fuel rather than pull the fuel. Mercruiser makes a kit for it.

[TeamAllen]

Mercruiser makes a kit that uses a secondary fuel pump to push the fuel from the tank to the primary fuel pump. The kit is more expensive than probably the other remedies, but well worth it in my opinion. It is engineered to work with your systems so all of the safety features are there. With fuel in boats, that was important to me. it plugs right into your existing wiring harness. Mercruiser has a TSB on this problem. http://www.boatfix.com/merc/Bullet/99/99_07.pdf

It is reposted here and has links to the different part numbers. I would search the part # at other sources for possible better pricing.

https://www.perfprotech.com/blog/art...ser-vapor-lock

The permanent remedy is a $400 Mercruiser kit. There are a few remedies to help reduce the chances of it occurring. Run the exhaust fan the entire time to keep airflow through the engine compartment. Add Sta-Bil Marine stabilizer to all of your fuel. Let the boat idle for a few minutes after pulling a rider/cruising and before shutting it off. If it still occurs while you're on the water you can put a cool wet rag or squirt water on the fuel lines to cool it back down. The key is to reduce or minimize heat. The ethanol vaporizes at a lower temperature than regular gasoline.

Some boats place the fuel pump in the fuel tank, like a car, to avoid this problem.

Here is another reason, in post #3 of this thread of why this tank of fuel might be problematic.
http://www.tigeowners.com/forum/show...ght=vapor+lock

[chpthril]

Vapor lock is typically an issue that occurs with the engine off and the engine bay is heat soaking. With the engine running, the constant circulation of fresh cool fuel from the tank, prevent the vaporization of the fuel, in the lines.

[Ruger761]

They are correct add the fuel pump by the tank and you wont have any issue with vapor lock again, or at least I never have.