Overheat and now stalling

[bruhaba]

2007 Four Winns Horizon 190 - Engine: Merc 4.3 MPI; ; Drive: Merc Alpha One drive; 61 hours on boat. Bought it as a leftover in spring 07'. It's my first boat and although very experienced with automotive wrenching, I'm just getting my start with boats.

I was in the process of winterizing today. I live in SC. Warmed up engine using muffs with the garden hose, all went well, thermostat opened and water came out exhaust like normal. I then changed the outdrive oil and engine oil and started her back up. I noticed that no water was coming out with the exhaust and after a few minutes of running, I hear the warning alarm and shut the boat down right away. The temp was at about 220 or so. I check the garden hose and it had water flowing and it was covering the intake on the drive.

I then waited a while and double checked the water flow and started back up, the engine was struggling to idle and eventually stalled. I tried again and it did the same thing.

Is it possible that the raw water pump somehow got damaged and is causing a lot of rotating restriction making it difficult for the engine to idle? Are boats really this fragile? Grr.

Any suggestions would be greatly appreciated. Thanks.

 

[scipper77]

Re: Overheat and now stalling

I have read posts where people trying to run an engine with an obvious problem did more damage to the motor. I can't really tell you the best plan of attack to fix your problem but I wouldn't try to start it again until you run a few checks that I'm sure will be pasted by the fantastic mechanics on this site in no time.

 

[JIGGER]

Re: Overheat and now stalling

Sounds like water is cutting out a cly or two.

 

[bruhaba]

Re: Overheat and now stalling

I definatley won't try starting it again. I drained the block after it cooled and put it back in the garage.

I certainly hope water is not getting to cylinders. The engine only has 61 hrs on it and the temp only went to 220 F. My truck with a 4.3 runs at 210 normally, 220 should not be hot enough to hurt an engine.

 

[JIGGER]

Re: Overheat and now stalling

One wouldnt think but... If a head gasket went youll know if you pull the plugs and see if water fills up a cly. Best way might be to pressurize the cooling system for an air test. You might hear a cly leak. Cracks wont affect it till the engine gets hot and puts water in the oil or cly. Head gaskets leak cold. Who knows made the plug wires got wet but I wouldnt leave water sittin in cly to long.

 

[captmello]

Re: Overheat and now stalling

You could pull the plugs and see if they're wet. Do a compression test while they're out. The thing about the boat motor is the exhaust manifolds are water cooled. If there's no water flowing the engine may not heat up as fast but the manifolds will. If the manifold cracks you can get water in your cylinders.

 

[Don S]

Re: Overheat and now stalling

Is the gas tank low? could be if you have the bow very low and the gas tank is low, you ran out of gas! Long hoses and low pressure has stopped the flow of water on many engines with good pump.
But do check the cylinders for water.

 

[mstng]

Re: Overheat and now stalling

I am probably the least knowledgeable one on this site regarding marine engine mechanics, but I can't help but wonder if the maintenance is somehow related.

What could have happened between running perfectly, doing a little maintenance, and then problems? Seems quite the coincidence.

 

[JIGGER]

Re: Overheat and now stalling

Not sure man but 220 is boiling so anything is poss.

 

[Don S]

Re: Overheat and now stalling

220? is hot, but it also doesn't destroy engines.

210? is also NOT NORMAL. Time to find out why. Destroyed impeller, who knows, but it would be the FIRST thing to check for. Who knows how many times that unsold boat was started without water hooked up to it.

 

[bruhaba]

Re: Overheat and now stalling

Nose was low, but tank is about half full.

Just pulled 4 plugs, 2 on each side and stuck a piece of vacuum line in the cylinder to see if there is any standing water. All plugs looked the same and no residual water. Of course, the boat has been sitting for about 3-4 hours now, so I'm not sure if I would see evidence of water. One thing that was odd was all the electrodes had a dark green tint to them. Anyone seen that before? Is that from the Stabil in the gas?

The 210 comment was about my truck with the same 4.3, not the boat. Normally, the thermostat on the boat opens at about ~180-185 and stays there. At least that's what it looks like on the gauge on the dash.

I struggle to see how changing the engine and outdrive oil could cause this. The initial overheating must have been due to one of the water pumps not circulating. The engine ran for 5-10 minutes before the alarm went off. Water never came out of the exhaust in that time period. Is there anything tricky that I could have done wrong while warming it up. It seems pretty straightforward. Put muffs on, turn water on, start boat? Am I missing something or is this a freak issue I have here.

 

[chiefalen]

Re: Overheat and now stalling

The t-stat should open at 140. A little higher.

Your still under warranty?

Did they give you a manual?

This impeller was on the way out long before this.

You get 3 years, 4 years out of a impeller in salt water.

Bring it back to the dealer.

 

[scipper77]

Re: Overheat and now stalling

if you ran for 5 minutes with no water exiting the exhaust I'd check the impeller. Of course before you listen to me ALLWAYS take into consideration whatever Don says. He is the master. Don't let his short and to the point answers mislead you.

 

[bruhaba]

Re: Overheat and now stalling

The t-stat should open at 140. A little higher.

Your still under warranty?

Did they give you a manual?

This impeller was on the way out long before this.

You get 3 years, 4 years out of a impeller in salt water.

Bring it back to the dealer.

Yeah, still under warranty...To the dealer it will go. I do have a manual...Followed everything in it as well as researched on the forum prior to doing the maintenance.

I don't even know what the warranty is that I have on the boat but it has to be at least a year, I bought it in March.

I've read some of Don's posts while browsing here and it is apparent he knows his stuff.

 

[chiefalen]

Re: Overheat and now stalling

Well you tell them what you want to tell them.

This hot condition was from day one you got it.

After they fix that problem, under warranty, and you test it then ask them what they get for the first winterization.

And the price should cover summerization for next spring.

I'm curious about the out drive oil.

Maybe you can watch them do that.

See what that looks like?