Boiling GAS!

[Pescado48]

Hello All,

So I launched the boat today for the first time this year. FYI..had new plugs and a new fuel pump put in this spring. Anyways started easy and proceeded out of the bay and into the lake so i could open it up. Ran it at full open throttle for a about 15min. Everything seemed fine so a thought I would try and do some trolling for kings. When I eased off the throttle I noticed quite a bit of white smoke coming from under the swim platform. I turned the engine off and open the engine compartment only to find it full of white smoke ( possible burn off of lube's used to remove very rusty spark plugs). I then noticed a bubbling sound coming from the carb?WTH..boiling gas in the carb. After the engine cooled most of the smoke vanished except for the air intake a steady stream of smoke would continue there for a while longer. Boat is running at 225F, seems hot. Any thoughts? I'm new to boating but would like to learn the in's and out's?thx for any help.

Pescado

 

[Pescado48]

Re: Boiling GAS!

Sorry I should of added some details, I have a 2004 merc 3.0L with Alpha one drive.

 

[dubs283]

Re: Boiling GAS!

Boat is running at 225F, seems hot. Any thoughts?

225 is overheating, big time

how long did you run the engine at that temp??

 

[Pescado48]

Re: Boiling GAS!

not sure how long it was at 225F but the whole boat ride was about 30min, boat ran great last year no issues, what would bring on these issues? I figured it would be running better after new plugs, new fuel pump, new oil, now its over heating?

 

[Bt Doctur]

Re: Boiling GAS!

dosent take long at that temp to pop a head gasket

 

[dubs283]

Re: Boiling GAS!

what would bring on these issues?

worn water pump impeller, debris covering sea water pickup in drive

one part of boating is constatnly watching your guages

like the doc says, does not take long running at 225 to cause head gasket damage, and other possible issues

 

[not enuf toys]

Re: Boiling GAS!

impeller shot, worn, frozen, broken, torn.....not working correctly.

 

[Pescado48]

Re: Boiling GAS!

What about the boiling fuel in the carb? is that normal?

 

[Bt Doctur]

Re: Boiling GAS!

it would be if the block was at 225 deg.

 

[not enuf toys]

Re: Boiling GAS!

I am not a professional by any means - I don't think you heard gasoline boiling, rather the water in the water jackets of the motor. the only fuel in the carb that is hanging out is in the float bowl, and there is not a lot there.

 

[UncleWillie]

Re: Boiling GAS!

What about the boiling fuel in the carb? is that normal?

Absolutely NOT!

Think about it. 225 is 13 degrees above boiling.
The block is NOT Pressurized so any water will boil at 212 at the most.
Anything dissolved in the water and any altitude above sea level will LOWER that temperature.
Water boils at 212 or less, so for the engine to be at 225 the could not be ANY water in the block, Just steam.

Forget the boiling Carb issue until you get the boiling block problem solved.
You should not see anything much above 170 when it is working properly.
You are more than 50 degrees into the Red!

 

[not enuf toys]

Re: Boiling GAS!

Forget the boiling Carb issue until you get the boiling block problem solved.
You should not see anything much above 170 when it is working properly.
You are more than 50 degrees into the Red!

again, impeller/water pickup

 

[UncleWillie]

Re: Boiling GAS!

... I have a 2004 Merc 3.0L with Alpha one drive.

Do you understand that an Alpha Drive, Like any other, requires annual maintenance.

As a minimum, the impeller will need to be inspected annually and replaced every 2-3 years at the most.
The Alpha Drive's Gear Lube Oil, Not the Engine's Oil, Needs to be replaced annually or every 100 hours of operation.
While the Drive is Off for the Impeller inspection, the alignment of the engine coupler with the Drive shaft needs to be checked.
These are just the Major items, there are more to check. Has the Engine Oil been replace since last fall? Coupler and Gimbal Bearing Lubed?

If you just park it in the fall and pull it out in the Spring, expect to be spending thousands of dollars on repairs that could have been avoided with a few hours of preventative maintenance.

 

[not enuf toys]

Re: Boiling GAS!

Do you understand that an Alpha Drive, Like any other, requires annual maintenance.

instead of making it a pain or work every year, make it part of your spring "lets get ready" projects! I do this every spring while I am getting excited for the weather to break. I make the projects take a couple of weeks by doing some here and there. By the time its time, everything is ready and I am re familiar with many aspects of my boat after the long winter. Makes on the water issues (if the arise) really easy to address

 

[Pescado48]

Re: Boiling GAS!

Guys just to be clear…I do not not have any mechanical background which is why I took the boat to a marine mechanic to have it winterized and again this spring for service and de-winterization. Would the mechanic have checked the things Uncle Willie has mentioned? Is these part of a routine de-winterization visit?

I also wanted to mention, after a little research I identified a hose. The sea water intake hose seemed to be hoping almost like it was back firing…Does this help identify the problem? I just do not want to go back to the marina blind and not informed..thx for all the help.

 

[Volphin]

Re: Boiling GAS!

Guys just to be clear?I do not not have any mechanical background which is why I took the boat to a marine mechanic to have it winterized and again this spring for service and de-winterization. Would the mechanic have checked the things Uncle Willie has mentioned? Is these part of a routine de-winterization visit?

I also wanted to mention, after a little research I identified a hose. The sea water intake hose seemed to be hoping almost like it was back firing?Does this help identify the problem? I just do not want to go back to the marina blind and not informed..thx for all the help.

Just tell them what you told us, and that you think it may be the impeller. And no, you have to request impeller service when you de-winterize. It is not normally addressed unless you ask for it because even though it is a good idea every year, you can normally get 3-4 years on an impeller depending on how many hours you put on it annually.

Probably a good idea to get the oil changed as well at those temps.

 

[Scott Danforth]

Re: Boiling GAS!

and I would suggest a compression test to make sure you didnt fubar the head gasket

 

[acdc96]

Re: Boiling GAS!

Could also be a bad thermostat... Just throwing that out their.
Frozen shut and unable to allow water into the block.
But get that impeller replaced.

Good luck!

 

[998cc]

Re: Boiling GAS!

Could also be a bad thermostat... Just throwing that out their.
Frozen shut and unable to allow water into the block.
But get that impeller replaced.

1. I'd check the thermostat as well.
2. Did the engine run without a good supply of water to the outdrive even for a minute or less? Even a quick dry run of the engine will quickly ruin a good impeller. I have the proof in my box of "experienced parts".

 

[UncleWillie]

Re: Boiling GAS!

Not to be doom and gloom... Let's assume the worst and hope for the best.

If the impeller shredded, and water flow was minimal for a few minutes; The block boiled and the exhaust lost all cooling.
Unlike a car, a boats exhaust is mostly made of rubber and plastic, not metal.
75% of the water pumped to the engine bypasses the block completely and is used solely for cooling the exhaust.
Without water and at "Full Throttle for 15 Minutes" the exhaust should be looked at very closely.

Looking back...

I have a 2004 Merc 3.0L with Alpha One drive...

That engine assembly has a High Water Temperature Alarm that should have been Screaming to warn of the problem long before any damage occurred.