Engine stall intermittently 2006 21V

[awolfinwater]

Hi all,

Recently picked up a 2006 Supra 21v with a 340 hp efi indmar engine.

Boat runs great with the exception of random stalling where the engine just shuts off. Mostly happens at idle but has also happened twice at speed of 20 - 25mph. In all occasions, the engine starts right back up.

Temperature hasn't been above 85 so I don't think it is a vapor lock issue.

I'm a first time boat owner and thought I'd reach out to the experts for suggestions.

Thanks!

[villain]

Check your fuel for water. We have had a big problem with that this year. About half the run problems with boats coming through my shop test positive for a good amount of water in the fuel. Check and make sure your fuel vent isn't under water when surfing. It would surprise you how many are.

[awolfinwater]

Thanks for the advice Villain I think I temporarily fixed the issue.

I checked the fuel filter -- couldn't blow through it -- so I replaced it. That still didn't solve the issue.

Villain, your suggestion led me towards the right direction. I very well may have water in the gas but my amateur mechanic skills couldn't figure out how to syphon out all of the gas (Suggestions appreciated).

Instead, I came across another thread that discusses the issues with using ethanol gas. The result is that the ethanol can cause phase separation hence wreaking havoc with water in the fuel tank.

The problems started occurring when I purchased gas from my local speedway, so this was a likely culprit. Even though they don't advertise the use of ethanol, I'm sure it is prevalent. Needless to say, I'm now strictly buying ethanol free fuel from now on from a local marina. The extra cost is worth preventing stalling mishaps with friends and family on the lake.

My temporary fix was using seafoam. Worked like a champ and haven't had any issues for the rest of the day. Will keep people posted if the symptoms return.

Meanwhile, if someone knows a good way to syphon out the gas, please let me know.

Cheers.


Sent from my Galaxy Nexus using Tapatalk 2

[villain]

Glad that I helped!!

[villain]

Mr. Gasket 12S Micro Electric Fuel Pump
http://amzn.com/B000BWCERY

This is what we use at the shop. Disconnect the inlet to the boats fuel pump and hook it to this. Use alligator clips on the battery. Pump it into a few 5 gallon cans. Don't run it in your car. I learned that the hard way. A call into my roadside coverage taught me that. Lol.

[awolfinwater]

I want to update everyone on the apparent cause of the issue.

After using seafoam, the boat worked great for a couple of days but the stalling issues returned. I decided to take the boat in for diagnosis and they determined that the problem was due to a bad ignition switch.

I did a little research on ignition switches and this makes sense if I'm having trouble starting the boat (which sometimes I do after it dies). But how does this fix explain the engine stalling? Doesn't really make sense to me.

I read in another thread by someone with a 2007 21v that they had grounding problems with similar symptoms as mine. If I still have issues after the boat returns, I'll look into that as a root cause.