Mercrusier 228 Overheating

[bdog221]

This is a 1984 Raw water system. Chevy 5.0L <br />Replaced water pump on engine & outdrive<br />Checked risers for blockage. None found<br />Replace thermostat & tested OK.<br />Good water flow from outdrive pump.<br /><br />Temp gauge OK at idle. Rises to Hot when RPM go to above 2500.<br /><br />Any ideas? <br /><br />If head gasket, how do I check for leakage.

 

[greenbrg]

Re: Mercrusier 228 Overheating

I pulled my block off plates from my exhaust elbows and when I am running off of the house water it reads 170 and when I am in the water it does not even break 100 but the water temp in the elbow reads about 140 from a different gauge, I have not figured that one out. But I was running around 220 off the house at idle before I pulled the plates. Let me know what you find. I pulled the elbow and exhaust off and soaked them in acid and brushed them clean to get all the metal bites.

 

[bdog221]

Re: Mercrusier 228 Overheating

Sounds like you changed the flow by running without the plates. I am going to try to run a compression test tonight. I was reading on another forum where the head gasket would cause an overheating problem. Also, in other post on I Boat I read a post topic: 'Cooling Question: Solved" They found a leak on the outdrive pump seal. I am going to pressure check this with a hose. I'll let you know if I find anything. Thanks for the reply.<br /><br />PS: What lacations are you checking your water temp

 

[Bt Doctur]

Re: Mercrusier 228 Overheating

"replaced water pump" using a full kit with base or just the upper kit.sometimes the base gasket lets go and hot exaust is sucked in the pump.dosent show up using a hose, exaust elbows/risers clogged.clogged thermostst housing.try testing without a therm.

 

[crazy charlie]

Re: Mercrusier 228 Overheating

How old are manifolds and risers????? They could be slowing the flow of water.Check the hoses that you had to re-attach from the risers and manifolds and tstat housing.I crossed them one spring upon commissioning and the motor did exactly what yours is doing.Charlie

 

[bdog221]

Re: Mercrusier 228 Overheating

I replace the base of the outdrive pump as well.<br />Forgot to mention that the guys who winterized my boat fryed the pump & housing. I also found the T-stat hose & riser hose was crossed on one bank. Today I checked the outdrive pump with muffs & pressurized it. Saw some water coming from the base near the inlet grates. Tightened it up & it went away. <br /><br />My boat is 20 years old & only used in freashwater. Today I cleaned out the manifold riser & probed them with a rod. Also flushed the elbows with acid. They were not that bad, some rust.<br /><br />No time to finsh, got dark. I will let you know what I find out or if you have any other things for me to try. Please let me know. Thanks for the help!

 

[bdog221]

Re: Mercrusier 228 Overheating

The only change I noticed was the temp gauge on the dash took longer to get to hot. Two issues I found were the crossed hoses & a slight leak ate the outdrive pump base. <br /><br />My next step is to try the clear hose on the raw water pump side & I will be testing with a infared gun tommorow. Although, excess water spilled on the intake manifold appeared to boil.

 

[bdog221]

Re: Mercrusier 228 Overheating

Checked out with infared gun. <br />Gauge Pos T-Stat Lwr Exht Manifold<br />Ctr 135 100<br />3/4 150 120<br />Full 170 140<br /><br />Engine never got hotter than 170 degrees.<br />Is this a normal running temp for higher RPM or still too hot?<br /><br />Also, clear hose test showed lots of bubbles. I suspect this is because I was running off the hose. Agree?

 

[bdog221]

Re: Mercrusier 228 Overheating

Problem solved. Had same problem as Crazy Charlie<br />crossed hoses at the T-stat from guys who winterized the boat. <br /><br />Thanks to everyone for the input! This is a great forum. Big help!<br /><br />When I contacted the dealer about the screw up, they told me they replaced the hoses the way they got em. Also they told me the impeller was burned up when they got the boat & had to manual fill w/ antifreeze. Sounds like a cover up for a poor employee!! Never had a problem last year. <br /><br />Anyhow, I was fooling myself with the temp gauge being too high (170 degrees) when running off the garden hose. Temp never got past 150 degrees when I was running in the lake. Suspect the air bubbles I noted with garden hose & muffs in place were contributing to the higher temps.

 

[crazy charlie]

Re: Mercrusier 228 Overheating

Glad to hear you got it!!!! By the way you are not the first here to have that very problem.I have suggested that at least 3 times before and 2 of the 3 were the same problem.Charlie