Engine overheating problem - Page 2 - Maxum Boat Owners Club

Jules660 · 08-01-2010, 07:54 AM

Hi,

Sorry this will prob be a bit late for you. I had the same prob last year and ended up blowing the engine. After the new one had been run in the same problem appeared. it took 6 months to prove the cause and problem. To save you the really long story change the prop !!! there is an article some where on the web that shows how the wrong cavitation can be caused by a prop that looks ok but has unseen damage.
Check for cavitation burns on your prop.

Mines all sorted now and thats after new engine, 4 impellers 2 thermo stats, exhaust plate change and a conformation leg change.

oh last thing if it had just been serviced check for the little rubber bit that goes on the drive chaft above the impeller housing.

again sorry prob a bit late

Best wishes

Jules

seapuppy · 08-01-2010, 04:54 PM

jules.
welcome to the zoo
.thanks for the info..if you could find article ..that would be great....but having damaged props shouldn't cause heating problems....would like to see the data that supports that..

SP
SP

Jules660 · 08-02-2010, 03:19 PM

Thanks SP,

I tried finding it for my engineers to read but have never found it since. The only way i can describe it is that the incorrect cavitation causes the cavitation bubbles to go the wrong way and thus being drawn up the water intake on the leg at above 1800 rpm.
when my engineer took the main water inlet pipe off whilst on the water we had loads of water coming in (pumped back out by the bilge pump) but as soon as we got above 1800 and on the plain the water just died off.

Bizarre i know and very unbelievable but it is true.

best wishes

Jules

tjwieseler · 08-03-2010, 02:01 PM

I would never have thought that prop cavitation could be the reason for the overheating problem. I know there are some cavitation pits on the prop. I will have to check it out.

I have replaced my engine with a new long block and have 7 hrs on it as of now. So far I have not seen the overheating, but I have not had the engine at WOT as of yet. The break-in procedure calls for 10 hrs before WOT, then after that only for a short period of time.

trburns · 06-27-2013, 09:35 PM

I have had a very similar problem and was interested to read the comments. Is there an online tech manual that shows how to access and inspect impellar on 2006 Maxum2400sc?

Quote:

Originally Posted by tjwieseler

I would never have thought that prop cavitation could be the reason for the overheating problem. I know there are some cavitation pits on the prop. I will have to check it out.

I have replaced my engine with a new long block and have 7 hrs on it as of now. So far I have not seen the overheating, but I have not had the engine at WOT as of yet. The break-in procedure calls for 10 hrs before WOT, then after that only for a short period of time.

mmwjr · 06-28-2013, 01:31 AM

tburns, your best bet is to buy an aftermarket mercruiser book for ~$35. What type of outdrive do you have? if it's an Alpha the water pump is located in the drive and you will need to remove the lower half. If it's a bravo the water pump is located on the engine, bolts on like the alternator does. You will need to remove he pump.

No matter which drive you have I would recommend replacing the impellor every 2 years. Also if you are going through te work to inspect it why not spend the ~$30 to replace it? Very cheap insurance concidering the result can be a $5K engine replacement.

jrsick · 06-28-2013, 12:12 PM

also check youtube, and mercstuff.com ("how do I") for good info on changing the impeller.

pascavone · 06-28-2013, 01:26 PM

you when from over heating, to loss of power to needing a new engine?

is your boat carbureted? and no water in the oil?

1. simple, hook the garden hose in to the raw water tube and crank it up, and watch the temp gauge.

2. you by pass the pump to trouble shoot it.

3. lost of power could just be vapor lock in a carbureted engine since your raw water is cooling the oil, fuel, and steering. (fuel expanding into vapor in the fuel line.)

4. sounds like a clog, or collapse hose if not raw water pump.

Try that then tell us what happen.

everything normal then its your raw water pump.

mmwjr · 06-28-2013, 05:40 PM

pas you lost me, who were you addressing. I didn't see anyone mention a new engine in the last 3 threads.

pascavone · 06-28-2013, 09:21 PM

I found two companies I am thinking about buying an engine from.......

middle of page 2

mmwjr · 06-28-2013, 10:41 PM

Got it. Blast from the past (2010).

Good luck and let us know how it works out

YNaut417 · 04-06-2015, 08:40 PM

Edrey1996: I believe I have exactly what you are talking about - the water intake hose has a kink, constricting higher flow at higher RPM'S. I will have the mechanic replace the intake hose along with bellows this year. I already went through these steps: impeller replacement (though we had no sealant around the housing- need to check that again), t-Stat was old and crusty, and took off one riser - not much bad in there. Only could go a few miles near marina last year. This year HAVE to get it right