Overheating problem

[204 Escape]

Went out for the first time yesterday. The engine in our boat, is a 5.0 Mercruiser carburated I/O drive.

The temp began bouncing between 175/200 degrees, and an alarm went off intermitantly.

I loaded up and came home.

Upon investigation, the "only thing that I found", was that on the opposite side of the prop, on the lower unit, there was a hole about an 1/8th inch in diameter, that was plugged up.

Could this be the problem ??

The unit upon loading up yesterday, only has 23.4 hours on it.

I don't get it !!!!!!!!!!!!!!

Boat was winterized by dealership.

 

[Chris]

Hi 204,

The hole you're talking about on the prop, it sounds like it might be a ventalation hole. Some props have those built into them and you can then plug them or leave them open. That way, you can more or less play around a bit with the prop for performance purposes.

As far as the overheat goes, as I stated in the other thread, the first thing I think about is either the impeller or debris in the system.

Any idea when the last time the impeller was changed? It's something that should get changed once every couple of years as a rule. Some people change them every year, some every few years and sadly many just ignore them until they break apart and then they end up with cooling issues.

-Chris

 

[204 Escape]

The boat only has 23.4 hours on it. I don't think I exp;ained it right.

On an outboard, I "think" this hole was for the speedometer. (I'm not sure).

I did clean out some debris, out of the hole.

Here's a "dumb question". Is there an impeller in the lower unit of the I/O unit ?? I guess that would make sense to have one, BUT, I hadn't given it a thought. Especially with the # of hours on it.

 

[Chris]

Hi 204,

Yeah, whether it's outboard or I/O they both have impellers. It's located in the lower end of the drive unit and it looks like a little fan of sorts. What is does, is it drives water up and into the motor.

And what can happen is that over time it starts to dry out and the blades can break off. Running it dry or sucking up debris can also damage it, wear it out or burn it up.

You mentioned you only have 23 hours on your motor, how old it though? They can dry out with age regardless of hours.

As far as the hole goes, not sure what you mean exactly. There should be a bunch of holes that are for picking up water on the lower unit. I'm not sure if that's what you mean.

Take a picture and post it if you like, maybe that will help.

Debris getting into the the water intake holes can definitely cause issues though if that helps. If you have flush muffs , doing a flush with fresh water might help to flush out debris.

-Chris

 

[Chris]

Here's a link to a site with a picture of what an impeller looks like.

http://www.sterndrive.info/sterndriveparts/impellers.html

-Chris

 

[Chris]

Here are 204's pics of his drive....

 

[Chris]

In the first picture that I posted, that is the main water pickup. That's definitely an area you want to make sure is clean of debris.

The other one with the small hole in the leading edge of the skeg I believe is for the speedo pickup.

The third picture is a bit hard to tell exactly what it is, but I think that might be the hole for the speedo tube.

While I was searching around for a picture of an outdrive, I stumbled on to this site which has some overheating tips.

Maybe it will help - here's a link.

http://www.performancemarine.net/overheating_problem.html

-Chris

 

[RNC]

I found your stats on your boat so we can help you.

2006 LArson 204 Escape
Weighs 3100 #'s (according to the brochure)
Has a 5.0 Mercruser Carburated engine
220 H.P.
50 gallon fuel tank (full)
Alpha one drive unit
20'-1" long
Modified...

The first thing I would do is have your water impeller changed. Hours do not matter what the problem with yours is that it is 3 years old. I personally change mine every year. All the alpha I have seen the water impeller is in the foot. The bravo's are mounted on the engine

 

[Chris]

Thanks RNC.

-Chris

 

[204 Escape]

Thanx, for the info. Are they as simple to change as one on an outboard ??

(I'm not a mechanic, just trying to figure out the labor cost).

 

[RNC]

Thanx, for the info. Are they as simple to change as one on an outboard ??

(I'm not a mechanic, just trying to figure out the labor cost).

Yes any Certified mech. can change this rather quickly. This is a common thing and they should be able to tell you right over the phone exactly how much it will cost right down to the penny.

 

[Chris]

Yeah, it's pretty similar to an outboard change. You're best to buy a complete waterpump kit and then change out the impeller and the rest of the related parts.

If you don't change out the other parts at the same time, it can wear the impeller out prematurely and then you're back at square one.

-Chris

 

[Fun Times]

Thanx, for the info. Are they as simple to change as one on an outboard ??

(I'm not a mechanic, just trying to figure out the labor cost).

More then likey the labor for just a alpha drive impeller would be between 2 to 2 1/2 hours Depending on the shop used. Then you will have almost 3qts of stern drive oil, plus impeller misc supplies and EPA waste, tax, So looking at that, My guess would be right around $ 300.00 with labor and all basic parts. Or if you need a compleate water pump kit then you might need to add another almost $80.00 or so to it for the hole pump kit, It just dependes on how hot the impeller housing got in between the upper and lower unit, If it got real hot then you wasted some other parts, But you will not know till you open it up.[Sorry]:yikes: Smile you will for get all about when you are back out on the water having fun. I hope this helps some, Good luck with it.

 

[204 Escape]

We got an impeller, lube, and labor, for $155.00

 

[Chris]

Hi 204,

Did the tech say what kind of shape it was in?

And have you had a chance to run your boat and see if it solved your overheat condition?

-Chris

 

[204 Escape]

We kept the impeller. It didn't look bad to me, but I'm NOT a mechanic. The temp, is still running at the 175* mark. I guess that that is o.k.

There is still an alarm that goes off intermittently. That is what the boat is at the dealership for right now. There are "3" other boats there for the same alarm deal.

I'm going to ask them to just replace the alarm, and see if that works.

Everything checks out fine. Temp., oil pressure, lower unit oil, etc.

 

[Fun Times]

Wow $155.00 is a good price to have that done, I know some places can do it for around that price and some places are running sales for service just to try to keep busy during the hard times right now. Here In CA our labor rate at our store is at $129.00 per hour. By the way the most commen problem to sound the warning horn on your engine would be a bad drive gear lube oil bottle sensor sending unit, It would get stuck down and ground it out to sound the horn, And normal it would stop if you unhooked both wires after a round 60 seconds or so. Or maybe after it got hot the engine temp warning horn switch is out of it's range and got stuck at a hi temp reading due to the switch is not grounding out to the intake manifoild or thermostat housing where ever it is mounted, Due to the sensor might have to much paint in that area blocking the ground to the sensor. But I am just guessing and giving ideas of what I have seen in the past. Good luck with it.