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Engine won’t start after taking on water

Pason87

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Looking for some advice.

I had a damaged impeller and wear ring. A friend came over to help change the parts but the impeller boot was damaged. We used the damaged boot. (Big mistake) After we replaced the impeller and launched the boat I was on the lake for about 15 min when the engine died, I could hear the bilge pump running and checked the engine compartment to find about 8 inches of water.
At that point I had another friend tow me back to shore.
Now that I am trouble shooting the engine will not start, the starter won’t engage, anyone have any idea what the problem could be?
 

sunbyrned

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I’ll throw this out for starters. Check to make sure the hatch to your clean out plug is secure. If not, the safety button may not be completely pushed down.
 

Pason87

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New development, the boat sat for a week. I just hooked up a garden hose and the engine did turn over, very slow but it did turn over.
Possibly the starter got wet and is now dried out?
 

sunbyrned

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I’m confused. Did you flush your engine before it actually started running? Is the engine working now?
 

Luc Lafreniere

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@sunbyrned FYI There are no clean out ports on Scarabs.

@Pason87 To the best of my knowledge, a broken impeller boot will not allow water into the boat. There are two possible water sources, the carbon ring/seal where the drive shaft enters the boat hull or the exhaust water intake/loop to cool the exhaust. The carbon seal requires that you have no damage to it and that the drive shaft/engine are correctly aligned, usually done by a dealer unless you feel very adventurous. If it's not aligned correctly, you can unevenly put pressure on one side, wearing it out and letting water in since a gap is introduced. Damage because of a rope or something of the sort can potentially cause significant damage as well to my knowledge. The exhaust system is cooled via lake/sea water. The engine is cooled via coolant (antifreeze) unlike Yamahas. The exhaust water intake is at the stern on the transom of the boat, it is not taken from the grate/impeller. The water is sucked in via a hole at that location and flows through the exhaust system and back out to cool it down. There are multiple clamps/hoses and a water box (aka muffler) along the way. It's important to ensure this path is all secured and has no leaks or damage. If so, water can come in very fast as well.

A for the starting of the engine, not sure on that one. If you had a lot of water and got the starter wet, what you're saying makes sense. But I can't intelligently comment on that one. The fact that it's now turning over rules out the "famous" relays that everyone seems to learn they need.
 

Luc Lafreniere

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Oh, also, the hose is not needed to just start the boat. BUT it is important to understand that you shouldn't run the boat out of water for very long (recommended no more than 30 sec at a time). The carbon seal is ONLY COOLED VIA LAKE WATER WHILE SITTING IN THE WATER. The hose attachment only provides water to the exhaust and is designed to allow you to flush it only. Regardless of this hose, it won't cool that ring. So careful! If you run it too long, you can overheat the carbon seal and cause excessive wear very quickly and allow a lot of water in the boat.

Also of note, since it sounds like you're relatively new to these boats, when providing water to the exhaust flush port, you MUST do it in this order: 1. start engine. 2. turn on water. 3. turn off water. 4 turn off engine. Essentially, no pressure should be provided unless the engine is on. Otherwise you risk hydrolocking your engine and causing damage once again.
 
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Pason87

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I was able to clean out the cylinders and spray with WD. Fired it back up and it died after a second.

I am now just replacing the impeller boot and wondering what I should torque down the nuts too. Any idea?
@sunbyrned FYI There are no clean out ports on Scarabs.

@Pason87 To the best of my knowledge, a broken impeller boot will not allow water into the boat. There are two possible water sources, the carbon ring/seal where the drive shaft enters the boat hull or the exhaust water intake/loop to cool the exhaust. The carbon seal requires that you have no damage to it and that the drive shaft/engine are correctly aligned, usually done by a dealer unless you feel very adventurous. If it's not aligned correctly, you can unevenly put pressure on one side, wearing it out and letting water in since a gap is introduced. Damage because of a rope or something of the sort can potentially cause significant damage as well to my knowledge. The exhaust system is cooled via lake/sea water. The engine is cooled via coolant (antifreeze) unlike Yamahas. The exhaust water intake is at the stern on the transom of the boat, it is not taken from the grate/impeller. The water is sucked in via a hole at that location and flows through the exhaust system and back out to cool it down. There are multiple clamps/hoses and a water box (aka muffler) along the way. It's important to ensure this path is all secured and has no leaks or damage. If so, water can come in very fast as well.

A for the starting of the engine, not sure on that one. If you had a lot of water and got the starter wet, what you're saying makes sense. But I can't intelligently comment on that one. The fact that it's now turning over rules out the "famous" relays that everyone seems to learn they need.
Thanks a bunch guys,
I ran a garden hose inside the engine compartment (on low flow of course) to see if any water would run out of the boat. The water was pouring from the damaged impeller boot. I replaced the boot and no more water problems. I believe I have that problem solved.

However, when I tried the engine again it started and ran for about 3-4 seconds and just shut itself down. It sounded kinda tight if you know what I mean.
I’m not sure if there is anything else I could possibly do and feel like I could have engine problems which is way above my pay grade. Thank you for all your help.
I was able to find a local boat mechanic as our marina shop has closed down due to COVID. He will be able to look at it in a few weeks. He is a prettt busy fella these days.
 

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Luc Lafreniere

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Well, I did not know that boot prevented water from coming in. Good to know! Yeah, can't help you on that engine problem. Good luck there and make sure to report back when you do find out. It's good for everyone to have a record and learn from it.
 

Sidarousmg

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did you pull the spark plugs to make sure there is no water in the cylinders? if you got towed and did not pinch off the exhaust cooling line, water can collect on top of the pistons and will not allow the engine to start. if you haven't already, remove the spark plugs and crank the engine. if water starts shooting out, you will need to remove all the water out before trying to restart. also, check the oil to make sure it was not contaminated.
 

Pason87

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did you pull the spark plugs to make sure there is no water in the cylinders? if you got towed and did not pinch off the exhaust cooling line, water can collect on top of the pistons and will not allow the engine to start. if you haven't already, remove the spark plugs and crank the engine. if water starts shooting out, you will need to remove all the water out before trying to restart. also, check the oil to make sure it was not contaminated.
You bet Sidarousmg,
I pulled the plugs, turned over the engine and also sprayed with WD. I didn’t know about pinching off the exhaust cooling line while being towed. Hopefully i won’t have to be towed again but I’ll read up on that just in case.

Thank you all, I will update when I get it diagnosed.
 

Gozills

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Oh, also, the hose is not needed to just start the boat. BUT it is important to understand that you shouldn't run the boat out of water for very long (recommended no more than 30 sec at a time). The carbon seal is ONLY COOLED VIA LAKE WATER WHILE SITTING IN THE WATER. The hose attachment only provides water to the exhaust and is designed to allow you to flush it only. Regardless of this hose, it won't cool that ring. So careful! If you run it too long, you can overheat the carbon seal and cause excessive wear very quickly and allow a lot of water in the boat.

Also of note, since it sounds like you're relatively new to these boats, when providing water to the exhaust flush port, you MUST do it in this order: 1. start engine. 2. turn on water. 3. turn off water. 4 turn off engine. Essentially, no pressure should be provided unless the engine is on. Otherwise you risk hydrolocking your engine and causing damage once again.
i dont want to offend anyone but the impeller boot has zero to do with water intrusion-period! If you have water in your engine wd 40 in your cylinders is not going to remove it
 

Pason87

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I agree Gozills, I’m still not sure what the issue is, I’ll find out tomorrow hopefully.

The damaged impeller boot was the culprit for the boat taking on water. It could be that it was just a coincidence and I had two different issues at the same time.
However I find that hard to swallow as the boat is a 2014 with only 45 hours on it, it ran great up until this point. Always serviced at dealership and stored inside during the winter months.
The only thing done recently was changing the impeller and wear ring. Unless sucking up some rocks somehow had something to do with it.
 

Luc Lafreniere

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Yeah, I don't understand how the boot can cause water to come in. But I'm not an expert on that since I haven't had any issues with mine. I agree with @Gozills , there must be something else wrong. To my knowledge, carbon seal, exhaust cooling system are the main water sources besides a hole/crack in your hull. I don't see how a boot can allow water in... the carbon seal/ring is what seals the shaft when going through the hull.
 

Winerocks

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If something wrapped around the boot and dinked it, it is also quite possible that it jarred the driveshaft and cracked the carbon seal. The carbon seal works because there is constant even pressure on it. If something wraps around the driveshaft, and pulls the seal apart, even a few mm’s, it can jump back and crack it. They are kind of brittle.
 
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