Axis Wakeboard Boat Forum

Sorry for the long post, but my question is, can FAE or any other issue cause an airlock on raw water pickup?

This past winter I installed a new FAE on my 2011 Axis A20 with dual exhaust. The FAE is the kind that has the exhaust lines that have to incline up and over the floating wedge, and then merges into the prop wash. I also opted for the butterfly valves to prevent water surges from entering the engine, if that makes a difference.

On my 3rd outing since I installed it, we launched the boat like normal where we let it idle while we pick up the driver and let it warm up before taking off. I noticed a plastic burning smell with white smoke, and realized the engine was over heating at 210F when I checked the temp gauge. I turned the engine off, closed the raw water emergency valve and checked the raw water impeller to see a fairly warn, (with a couple torn veins) but not completely destroyed 1.5 year old impeller.
Lucky enough I had a spare impeller (at least 2 years old, never used), replaced it while I was on the water, opened the emergency valve and then went to test it to make sure the engine was cooling. After about 10 seconds, I saw that the engine temps weren't dropping, so I shut the engine down to see what was happening.
I removed the hose that leads from the impeller into the transmission cooler. I noticed not much water was in that hose. I stuck my fingers inside the transmission cooler to see if anything was clogging it, and all I felt was the heat exchanger inside. Nothing I could have felt with my fingers was clogging it up. (as a note: On previous winterizations, I have found a few pieces of impeller veins inside, so I figures maybe more have found their way since last replacing the impeller 1.5 years ago. I also noticed when I drain that same hose, there is a significant amount of water sitting in it)

Next I wanted to verify that there was water being pumped from the impeller, so with the hose to the transmission cooler still disconnected, my wife started the engine for a total of 3 seconds and then shut it off. For the 1st second, nothing happened, but then on the 2nd second, water started flowing from the impeller and then also backwards from engine through the transmission cooler, inwhich I told her to turn off the engine right away.

I reconnected the hoses and started the engine again. Then I noticed the engine temps dropping. For the remaining part of the day I watched the temps, and noticed that it seems to bounce around a little more than what I remember. I can watch it bounce around from 165F-170F while idling, to 160F-165F while cruising, then 155F when coming off plane. Normally it used to just hold at 160-165F the entire time with very minimal change.

The next 3 outings since then, I noticed that on every 1st startup after launching the boat from the trailer, I know I'm not getting water circulation because the exhaust starts to have the classic white exhaust and plastic burning smell before the engine overheats. I did notice that if I get on plane right after launch, that gets the raw water flowing through the exhaust and then I never have that issue for the rest of the day. But then it repeats when I go to launch the boat the next day.

So my question is, what's going on? Is it an air lock, clog or something else? Is it related to the FAE? Did I just happen to have an old impeller that just disintegrated.

Any tips on something to check is greatly appreciated. I store the boat 1.5hours from me, so troubleshooting is a little difficult.
I plan on checking the impeller again as I picked up another spare, but I'm worried that might not be the case.

The best tip I can give you is you are paranoid. The exhaust does weird things and you are focusing on it too much. The raw water pump is designed to push water through the engine, hence why it is part of the belt system and comes before flow to the engine. Airlock shouldn't be an issue if your FAE has the hole on each exhaust manifold that is also used for drainage of the exhaust system.

Basically the raw water pump has a lot great pressure pushing water through the engine vs the water pressure pushing against it.

Wouldn't be a bad idea to give the throttle a quick rev when you first drop it in to get the suction started.

it's not uncommon for temps to bounce around up to 170. The engine is still within it's operating parameters up to about 180.

I do understand that the engine temperature can fluctuate, however on initial startup after I launch, if I don't get on plane, there is not any water being flushed through the exhaust. This is evident because I can smell burning rubber and see visible white smoke while I let the engine warm up and if not addressed it will overheat. While the engine temperature might not read hot as soon as I see smoke, there is an issue because the exhaust is hot enough to start melting the hoses.
Also, there was an incident where I was in a shallow no-wake zone for a while in which I did get temps over 190 and climbing till I was able to get on plane and then the engine started cooling.
I've put over 250 hours on the boat over the 1.5 years I've owned it, and this has never happened before.
To me, it is apparent that there is a circulation issue. I'm not exactly sure of what's causing it, but I just wanted to rule out the new FAE isn't causing it or another known issue isn't out there.
This is the order in which I'm going to check for issues, so if someone with experience with this issue, please help me out.
1. Check v-drive raw water hose inlet/outlet is clear of debris, or cracks.
2. Check transmission heat exchanger is clear of debris.
3. Check Raw water impeller isn't damaged.
4. Look over hoses, impeller housing to check for air leak. A air leak can make the raw water impeller loose suction and run dry.

If all of those look good try giving the throttle a blip as soon as you start it up.

I've seen this before on another brand. It was taking a while for the boat to get a good pickup of water going for the raw water pump. The blip got it going fast.

I've had an brand new impeller that simply failed. I don't know what was wrong but it never created the head pressure to pull water into the system at idle. I never bothered to try putting the boat on plane because I didn't want to risk anything. For a 30$ part, I'd try and replace it.

I agree it doesn't sound right to me. My only thought is an air leak on the inlet side.
Good luck!
Salem

My 2014 A22 is doing the same thing. I don't think it's circulating water through the exhaust at all. I replaced the impeller but after running it at idle for about 2 min I noticed it was running dry because it started to smoke. If you figure it out please let me know. I will be trying to do the same.