95 Speedster: Engine died at speed in heavy chop - No crank/power.

[egoods]

Greetings! First of all I have to send a big thanks to everyone on this board for helping me familiarize myself with my boat, learn about common issues, etc... Especially dwhee87 who was able to supply me with two new reverese cable levers after mine broke (see his thread about that here). This may be my first post but I've been lurking/searching for the past month.

Anyway, I have a 1995 Speedster with the twin 657x engines. I've had the boat for about a month, so far I had a spark plug that caused a no-start on one engine due to a corroded connection, and the aforementioned broken reverse cable lever (simple, but discontinued part... if you're searching send dwhee87 a PM, he may have a couple left still) it's been running like a top.

Until this past Saturday, I was out on a "big" lake (Lake St. Clair for any Michiganders out there) in pretty heavy chop... well, extremely heavy chop for this boat. At speed I was getting launched well out of the water. about 15 minutes in to my cross-lake adventure the port side engine stalled out. No beeps or warning, just straight cut out. I hit the starter button and it cranked VERY slowly, after that it wouldn't crank at all. Fearing an electrical issue I left the other engine running and limped it the couple miles back across the lake and back onto the trailer. Once up on the trailer I decided to hit the button and see if it would crank, sure enough it cranked and started right up.

Here's my thoughts on the cause and what I've checked so far. I'd really appreciate some feedback:
The bouncing/jarring may have knocked a connection loose? - I've since checked all grounds/connections and nothing seems loose or corroded...
Bouncing starved the engine of fuel/oil? - Both levels were fairly close to full, and why would I get no crank at all?
Overheat due to air in the cooling system (...from the bouncing)? - The engine was quite warm, no alarm sounded, maybe the starter solenoid was binding up from the heat?
Will the MPEM not allow an engine restart if it shuts one down to to a fault like overheating unless I turn the key off-back on again?
Other engine ran fine (though only at 3500rpm) all the way back.

Both engines had 140-150psi when I did a compression test last month, I will re-test today. I'm also going to re-re-re check all the wiring as the previous owner did kind of a hack job when they converted it to a single battery (I've repaired that, but it speaks to how they may have fixed other wiring).

Any input is greatly appreciated.

Oh, and I LOVE this boat! I've had it on a smaller lake a handful of times, and during the week on St. Clair as well and it's a total blast, it was even fun in the heavier waves (I'd say as big as 4-5 feet) but I don't want to put the boat through too much of that... not to mention the abuse it puts on my body!

 

[Dr Honda]

1) I doubt it was overheating because of air. If you were moving forward... then you were pumping water into the engine. Also... when an engine overheats... it generally looses power as it gets tight. (it's not an instant off kind of thing)

2) Does your boat have a key switch? If it does... then it really doesn't have an MEPM as we know them.

3) The MPEM doesn't keep an engine from re-starting if there is an issue.



Knowing that you were bouncing around... I'm more inclined to think that there is a loose connection somewhere. It may not be battery or ground issue... but it could be anywhere in the electrical system. I would start with double checking the battery cables... but I would also open, and re-connect any plug you can find.

Oh... also... lead batteries don't always like to be bounced. They are heavy, and full of water/acid. SO... you can get internal plates that touch. If that happens, the voltage will drop. That could result in a shutdown and a hard re-start until they float apart. So... is the battery in good condition? Is it a good brand??

I would carry a volt meter with you for the next few rides. If it happens again... check the battery voltage.

 

[jimmaki]

Could the port pump possibly have pulled in some weeds stalling the pump and engine? Maybe with all the wave motion it was flushed back out of the pump by the time you got back to the trailer. Weeds may also have blocked or clogged the water intakes and the engine overheated and started to seize, but cooled down by the time you reached the trailer.

 

[Matt Braley]

The 95's have a cheap riding mower style key switch. I have had them go bad and randomly shut the boat off when bumped. You can connect the two wires behind the switch to simulate it being in the ON position. First I'd slap that area with your palm and give the key a slight wiggle while running to see if you can duplicate it shutting off.

 

[egoods]

1) I doubt it was overheating because of air. If you were moving forward... then you were pumping water into the engine. Also... when an engine overheats... it generally looses power as it gets tight. (it's not an instant off kind of thing)

2) Does your boat have a key switch? If it does... then it really doesn't have an MEPM as we know them.

3) The MPEM doesn't keep an engine from re-starting if there is an issue.



Knowing that you were bouncing around... I'm more inclined to think that there is a loose connection somewhere. It may not be battery or ground issue... but it could be anywhere in the electrical system. I would start with double checking the battery cables... but I would also open, and re-connect any plug you can find.

Oh... also... lead batteries don't always like to be bounced. They are heavy, and full of water/acid. SO... you can get internal plates that touch. If that happens, the voltage will drop. That could result in a shutdown and a hard re-start until they float apart. So... is the battery in good condition? Is it a good brand??

I would carry a volt meter with you for the next few rides. If it happens again... check the battery voltage.

Good info, I'm still learning so I appreciate the level of detail.

The battery currently in it is an interstate from 09, it is lead acid and the thought already crossed my mind about it bouncing around. I was planning on swapping to an Optima blue top soon anyway, guess I'll stop delaying and grab one today. I'll also check all the wiring when I have the battery out.

The 95's have a cheap riding mower style key switch. I have had them go bad and randomly shut the boat off when bumped. You can connect the two wires behind the switch to simulate it being in the ON position. First I'd slap that area with your palm and give the key a slight wiggle while running to see if you can duplicate it shutting off.

Wouldn't that kill both engines though? I'll give it a shot, I just assumed anything with that would do the same thing to both.

Could the port pump possibly have pulled in some weeds stalling the pump and engine? Maybe with all the wave motion it was flushed back out of the pump by the time you got back to the trailer. Weeds may also have blocked or clogged the water intakes and the engine overheated and started to seize, but cooled down by the time you reached the trailer.

this seems unlikely, this lake has very few weeds, and I was mostly in depths well over 20' for a majority of the day... I'm going to pull the jet pumps soon anyway, and like I said I'll recheck compression as well, if it came anywhere near seizing I'm sure I'll see that reflected in a compression test.

 

[egoods]

Well, good news and bad news. After replacing some wiring, re-doing a few connectors, and putting the blue-top Optima in I have no issues with it cranking. But, I went to test it today, and after planning out it ran great for about 10 minutes before it stalled out again.

I put my hand on near each engine and it did seem to be hotter than the other engine. Is it possible the temp sensor is not functioning and this explains why I get no overheat warning?

After letting it cool for a while it will start right back up.

Anything else besides cooling that can cause this? Also, is there some sort of thermostat that I can check? Could it possibly be a stuck choke?

Any ideas would be appreciated!

 

[Dr Honda]

Sure... the sender could be bad. It's not a common issue to have the sender in the head go bad... but it does happen. BUT... what is more common, is to have your beeper go bad.

Try this....

turn the key on, so there is power on the system. (don't start the engines) Then, pull the wire off the top of the sender, and then ground it. Normally the best spot for a clean ground is the base of a sparkplug. It may take a few seconds for the buzzer to turn on... but once grounded, you should get a warning.

If the buzzer comes on... then check the sender. (Pot of water on the stove is the easiest way) FYI... the sender body is thin brass... so if you take it out to check... DO NOT tighten it too hard. They are known to snap off. Just put a little thread sealant on the threads, and screw it in.



Oh.... one last thought... take a multymeter, and just check the temp sender body, to ground for continuity. There could be enough corrosion that you simply aren't completing the circuit.

****EDIT****

The Rotax engines don't have T-stats. SO that's not an issue. If there's a blockage... its just from junk in the hoses, or engines. I guess if I suspected an over-temp... I would start to pull hoses, and blow though them with compressed air to make sure things are clear. AND... I would probably take off the head. Sometimes you can get a lot of sand that settles into the cyl's. IF you find that... you can break it up with a long screwdriver, and suck it out with a shop vac. Your engines don't have a standard head gasket... so as long as the O-rings are still pliable... then you can just put it back together.

 

[egoods]

Well, it's not good news. I was finally able to compression test the engine and one of the cylinders has no compression... zero, doesn't even register on the gauge. Obviously, that's my issue. I did ground out the temp sensor wire and the beeper worked so at least I know my temp warning works!

I've read good things about Seadoo Engine Shop around here and elsewhere, so it looks like that's who I'll go with. Any thoughts on whether I should do just a top end rebuild or go for a full rebuild? It appears the other engine was replaced sometime in the past few years (judging by the brighter white paint and a holographic sticker on one of the head cover bolts...), that engine also has good compression (130-140). Thanks again for all the help!