225 hp overheating

[bimmernut]

I just installed a '93 Evinrude 225, compression around 120 on all 6 cyl., overheats within 2 minutes. Starboard bank gets 40 degrees hotter than port. Both thermostats open at 140 degrees and close around 130. There is a pressure relief valve in-line between the thermostats, is there a way to test this? How do you clean the passages? I have heard of pouring tidy bowl down the thermostat passages, is this a good idea? Thank you for any info.

 

[qflex1115]

Re: 225 hp overheating

i have never heard about putting tide bowl in the water passages, then again i've only worked on boats for 2 years. but anyways i would try taking the thermostats and pressure releif valves out and blow air threw the nipple coming from the waterjacket and feel and listen for air coming out of the thermostat holes.

also is the waterpump old or been replaced recently? is there a strong flow of water coming from the pisser? i would also check the cyl. heads because thats where the temp sensor screws into. also if the engine is not flushed out the salt can build up and block the water passages.

also have you checked the actual temp on the heads? on each cyl? are they the same? you might need higher thermostat (around 150-160) maybe? thats as much as i can think of for now, hope that helps

 

[bimmernut]

Re: 225 hp overheating

I used an infrared thermometer, and the starboard bank is about the same temp top to bottom. I'll try blowing air through, the **** stream seems strong. Thank you for timely response.

 

[aguitarestv]

Re: 225 hp overheating

you can also try flushing out with vinegar to help break up salt deposits, if thats where your problem lies, and is water pump still good?

 

[Faztbullet]

Re: 225 hp overheating

That "check valve " is a poppit valve and it dump excess water pressure into water jackets at WOT. If motor is overheating replace the impeller,gaskets and wear plate EVERY year, if this has been ran in salt/brackish water you will need to check ALL passages in heads and block(closed deck design)for restrictions.

 

[bimmernut]

Re: 225 hp overheating

I took out the thermostats, blew air thru and now the heads both read about 140 degrees, so that is good. But I still get an alarm which beeps about every second. The VRO is disconnected, the former motor was a '98, replaced with a '93, so the harness had to be changed. None of the gauges seem to work so could that set the alarm off? I sure appreciate all the responses. You guys are great as is this forum.

 

[qflex1115]

Re: 225 hp overheating

what alarm is it? if its the temp wire disconnect it (its the brown wire) on the sensor in the cyl. head. pull that out and see if its the alarm. or make sure the right plug was pulled on the vro and not 1 of the 3 that is coming from your harness(wich is probably why ur guages aren't working.)

 

[bimmernut]

Re: 225 hp overheating

It's the vro alarm, as it beeps every 2 seconds. I'll check the wires tomorrow. There is a plug coming out of the engine with a brown wire and a black wire, and a plug from the boat with the same color wires but the connectors are different. I'm pretty sure that it is the vro wire in the engine, should they be connected even tho the vro is disabled?

 

[kenmyfam]

Re: 225 hp overheating

If you are not using a VRO / OMS system then you do not need the low oil or no oil warning anymore. Should be disconnected.

 

[qflex1115]

Re: 225 hp overheating

yeah disconnect that plug, thats whats giving u a low oil alarm

 

[bimmernut]

Re: 225 hp overheating

Is that the plug in the engine with a tan wire and a black wire? If so, it was disconnected and the alarm still sounded.

 

[liquidcommotion]

Re: 225 hp overheating

I took out the thermostats, blew air thru and now the heads both read about 140 degrees, so that is good. But I still get an alarm which beeps about every second. The VRO is disconnected, the former motor was a '98, replaced with a '93, so the harness had to be changed. None of the gauges seem to work so could that set the alarm off? I sure appreciate all the responses. You guys are great as is this forum.

By any chance did you notice clearing of the lines when blowing air through? I believe i have the same problem I found a chunk in the relief valve between the thermostats that "may" be gasket material it has me worried. Did you blow the air in through the pisser? I will be giving this route a shot soon, My engine was running fine last weekend I put some new plugs and wires on just cause and was letting it idle and noticed the temp shooting way up. Thanks