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2018 LSV Overheating

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Hi folks - 

For those who don't care to read the context: On a Raptor 410, where can I clean out debris that is upstream from the impeller housing? Something is restricting water flow and I had a brand new impeller blow apart. So now I get to fish impeller veins out as well. But I don't know where to start searching.


We've owned our 2018 23 LSV since new. I've had the dealer do most of the maintenance on the boat, but over the past year have begun taking it on myself (mostly since I moved away from the dealer and it was a pain to haul the boat that far). I have pulled and put in a fresh impeller/gasket every spring along with oil changes, etc. etc. The whole nine yards. The dealer performed a coolant flush/fill/burp/etc. about 2 years ago.

Over Memorial Day weekend, the boat threw an error (EMWT2 Higher Than Expected Level 1 - SPN:442 FMI:15), which after researching I learned is related to the engine temp rising too fast. We shut the boat off and started it back up a few mins later... error cleared and boat stayed at 165 degrees all day. The next day, it did the same thing, but wouldn't clear after stop/start. So, I cleaned the sea strainer (minor debris... not much) and pulled the impeller. The impeller still looked brand new, but I put in my spare anyway. Started the boat back up and engine temp immediately dropped from about 175 to 145... then climbed to 165 and stayed there the whole day.

Monday (Memorial Day), it does the same thing... again. This time, the engine temp rose crazy fast and hit 200 before we realized and shut it down. Opened the impeller housing and several of the impeller veins are broken/missing. So, clearly, it ran dry for several mins.

So, to restate the question: having cleaned out the sea strainer, replaced the impeller, gasket, etc.... where do I look next for blockage? The discharge/upstream portion of the impeller housing seems to go directly into the heat exchanger... is there no cleanout/filter? HELP! :)

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Same issue here just occurred on a 2015 22 VLX at a spring startup.  I've had boats for my whole life and fix a ton of things myself.  I've learned to do an annual spring startup without anyone waiting to get on the water. I charge batteries, clean everything. check oil fluids, and watch the engine as I start it.  I've found broken strainers, hoses, bad t-stats, dead batteries, alternators etc. 

Just today, I started the engine and it ran nicely for 15 mins.  Then I noticed the temp up near 170 and shut it down.  Looked at the engine and didn't see anything funny.  I resrated it i and the temps went 150-16--170-180 pretty quickly.  I am so fortunate that I was watching it as I shut it down and pulled the impeller as I had not changed it in 3 years.. just forgot in the fall and didnt use it much with COVID shutting the ramps down here in TX.   Not surprising, but the impeller fins were broken and missing.  Sequentially took the whole water system apart to find the broken fins as I wanted to be sure they didn't end up like a beaver dam somewhere blocking all the flow.  Indeed the broken impeller fins end up in the heat exchanger on the drivers side near the back of the boat, which has what would be like a shower drain in it.  Small pieces probably flow through the whole engine and likely just flush out with the water.  It took me an hour of taking almost impossible hose clamps off in the boat to get to that point.

After replacing the impeller I could not get suction.  I've read the fin orientation matters, but I figured they would sort themselves out... I guess I'm wrong.  Getting NEW impellers out is really hard on a 22VLX as the pump is under a bunch of stuff and needs to be done blind/by feel.  So I ripped the new impeller and have a couple new ones on order.


For those curious - the water flow in my 2015 22VLX s the following (Reversed engine, so for orientation purposed here it is based on bow being FRONT):

1. Lake Intake pipe (Front Right)
2. Strainer (Right Side) followed by 4' long hose.
3. Impeller pump (Back)
4. Long Hose from back to front (4')
4. Transmission in (Front Left)
5. Transmission
6. Transmission out (Front Right)
7. Long hose from front to back (4')
8. Heat exchanger (Back top right) THIS IS WHERE IT JAMS
9. Thermostat Housing (Right back)
10. Thermostat housing pass through to left heat exchanger.
11. Thermostat (and engine block when OPEN)

After that, water is in block and both exhaust manifolds.


So the impeller fragments flowed through water lines nearly 360 degrees around the engine before jamming.

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Curious to hear the proper answer on the 18 Raptor as that is what I have. Looks like you would need to cut the Oetiker clamp to remove the hose were the water enters the heat exchanger. It is down low and looks like it would be a real pain. Not like the old days of pulling the hose at the oil cooler and just cleaning them out there.

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In the normally aspirated Raptor engines the sea water is drawn from the hull inlet, through the vee drive, to the crank mounted raw water pump, then pumped to the engine oil cooler, to the transmission oil cooler, and then into the engine coolant heat exchanger.  From there is goes from the heat exchanger to the exhaust manifolds, to the catalyst exhaust pipes, then down the exhaust hose and out of the boat at the transom.

A failed impeller will likely clog the inlet of the engine oil cooler first on those engines

On the supercharged engine, the raw water pump pushes water through the charged air coolant heat exchanger on the front of the engine before going to the transmission oil/engine oil cooler, then to the engine coolant heat exchanger.

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5 hours ago, begeland said:

Small pieces probably flow through the whole engine and likely just flush out with the water.

No.  See @csleaver's description above.  On a closed-cooled engine, the engine side of the heat exchanger has coolant mix ("antifreeze") in it, and the raw water side has raw water in it.  Your impeller chunks cannot get into the engine.

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This may be a dumb question, but did you get under your boat to make sure the intake underneath isn’t clogged up or have algae/moss/weeds stuck up in there to block the flow of water?

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On 5/31/2022 at 8:49 PM, snarohyans said:

So, to restate the question: having cleaned out the sea strainer, replaced the impeller, gasket, etc.... where do I look next for blockage? The discharge/upstream portion of the impeller housing seems to go directly into the heat exchanger... is there no cleanout/filter? HELP! :)

If you are having problems with a new impeller failing, I would check the sea water inlet under the boat, the shutoff valve attached to the inlet, and the seals on the sea strainer cap and hose flush.  A loose hose connection, worn clamp, or damaged hose from the hull inlet, to the vee drive, or to the raw water pump could allow the sea water to become aerated and damage the impeller, also.  Even a leaking seal in the sea pump could cause problems.  I have even seen layers of the inside of a water hose come apart and create a blockage.

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