200HP Yamaha motor loses power - question

[boslaw]

I have a 1997 200Hp yamaha 2 stroke motor. Never had a problem with it before. On Sunday, I suddenly lost power while idling, after a full day of riding around. Tried to start up again and couldn't get the motor to turn over. Seemed like a battery issue (batteries showing 12.4 volts). I was able to get started by using both batteries simultaneously, and I limped back to my slip. The motor sounded funny - almost like a wheezing sound. When I got back to the slip, I backed off the throttle and the motor died again. The only "problem" I could find is that the flush hose on the underside of the motor was loose, and water was running out. Could this have caused my problem? I would think that maybe my batteries just need to be replaced or battery cables tightened (forgot to check while I was there), but would that also explain the wheezing sounds? Motor definitely didn't sound normal after the initial loss of power.

Thanks,
Andre

 

[bayrat]

Did you ever get an "overheat" alarm at any time while the flush fitting was loose and leaking water ?

 

[boslaw]

no alarms at all. Just the wheezing sound when I got it started again. It was very weird and happened suddenly after a great day of riding around without any problems.

 

[bayrat]

I was thinking that possibly you overheated and it was hard to crank because of the expansion. Have you tried to start it recently since its had time to really cool off? Take a look at the oil level/ condition. The fact that it happened while you were idling and that the engine sounds strange makes me think that it's something mechanical rather than it being a battery problem. Hopefully some other members have a few ideas

 

[boslaw]

Thanks. I'll be back to the boat on Saturday. I'm hoping it was just the flush hose.

 

[grady33]

Don't know much about those engines but it is my understanding that the engines will slow or shut down when overheating. I actually had that happen once when a bag got sucked in the intake area. We couldn't figure out what was going on until we raised the engines and found the bag. Afterwards, all was back to normal.

 

[Daman858]

Grady 28 is correct. That engine will shut itself down when overheated and will not let you run it again until it has cooled down.

 

[DaleH]

An OB "wheezing" sounds like a lean sneeze from your needle valve setting. OBs with a SLOW (Speed Limiting Overheat Warning) mode limit the max RPMs and change the timing so she'll shake like Courtney Love on crack at a metal concert. This timing adjustment is intentional so you do not even want to put any RPMs to her. I find it hard to believe any overheat mode could be enabled without the overheat warning tone (usually a solid constant tone) and warning light.

Yams are known, however, for slow idle speed "overheating" issues (no alarm or light) where usually the RPMs are set to low in gear and there's not enough water flowing thru the cooling path. Also check the poppitts on the thermostats, as this is another area of issues with Yam motors.

 

[boslaw]

The weird thing is that, if I ignored the odd sound, I think I could have cranked the throttle and been fine. It only stalled when I dropped down to idle. I was being cautious because of the noise and that's why I limped back to the dock at 5mph. As for overheating, it WAS 90 degrees out, and I had been racing around for a few hours, but the pee hole seemed to be shooting fine and I'm pretty sure nothing got sucked into any of the intakes. I'm going to do a compression test this weekend and look around to see if I can find anything else amiss.

 

[boslaw]

checked compression last night - all cylinders at 120psi. Flushed with fresh water for 20 min. Nice strong steady stream of water.

Took the boat out this morning - started up fine. Drove around for about 15 min. Warning tone came on and stayed on and I couldn't restart. Sounds like overheat warning as everyone suggested. Got towed back to the dock.Now what? I can't see anything visibly wrong. After overheating, it seemed like both batteries were also too low to crank. 2 hours after overheating I tried to start it up again but I couldn't get any juice. Battery terminals are connected nice and tight.

 

[DaveH2Ofowl]

I had a problem with the over heat alarm going off. I shut off the motor for a little bit and start it up again and it would run fine no alarms. Every thing looked fine, water was coming out of the p hole and the water was not hot.I had the problem durning the summer when water temps. are higher, no trouble in the spring and fall. Had new emplellers installed in water pump but still had intermitten problem. I bought 2 new thermostates and install them. I tested the old ones in boiling water and one of them was bad it would not open all the way. I have not had a problem with this anymore.

 

[bayrat]

Being that it started up fine when it was cold I'm guessing that its an overheat condition (irregardless of lack of alarm)which causes expansion in the cylinders. That could be why you needed both batteries to start it the first time, and as someone else suggested, you went into "limp" mode. If it was anything else I would think that it WOULDNT start and run normally when cold. Maybe you picked up a plastic bag and fried the impeller, have a blockage somewhere or as Dave h20 said , bad thermostats. Can you borrow a laser temp gun and check the engine temp when it's running?

 

[bayrat]

I just noticed that you said an alarm went off this time...but you said no alarm went off the first time. When the alarm went off this time did you look at your engine temp?

 

[boslaw]

went back to the boat today with a brand new battery but I couldn't even get the motor to turn over. Seems completely seized. I pulled what I think are the t-stats or some kind of valve (under a cap at the top of each head, black rubber with a metal core and a spring). They seemed fine - I could move the spring with a tool, but they looked kind of old. I think I'm at the limit of my capability, especially with the boat in the water. I'm going to get towed to a mechanic to have a pro look at it. I appreciate everyone's advice. I'm sure you're all on the right track. I just can't really take it apart while it's in water, and the fact that it's now completely seized has me a little freaked out. I'll post back with the final result after the mechanic looks at it.

Andre

 

[boslaw]

bayrat - I don't have a temp gauge on my boat. It's a 1997. I don't have a temp sensor either. It didn't seem hot yesterday. It shut down after approx 20 min of easy riding.

 

[boslaw]

The mechanic just called and said that my lower unit had a lubrication failure, which caused the lower unit to overheat and seize. He recommends a new lower unit ($2600) but he could rebuild for $2100. Do these prices sound reasonable for new england? $2600 is a lot to throw at a 1997 motor, but it's better than a new powerhead or new motor.

Thanks

 

[DaleH]

went back to the boat today with a brand new battery but I couldn't even get the motor to turn over. Seems completely seized. I pulled what I think are the t-stats or some kind of valve (under a cap at the top of each head, black rubber with a metal core and a spring). They seemed fine - I could move the spring with a tool, but they looked kind of old. I think I'm at the limit of my capability, especially with the boat in the water. I'm going to get towed to a mechanic to have a pro look at it. I appreciate everyone's advice. I'm sure you're all on the right track. I just can't really take it apart while it's in water, and the fact that it's now completely seized has me a little freaked out. I'll post back with the final result after the mechanic looks at it.

Could be the lower unit! My brother's '88 Yam 150hp "locked up" and we thought he had lost a ring/cylinder, as it wouldn't turn over, but it turned out some part near the clutch dog let go and was binding up the crankshaft.

 

[Sailfish25]

$2600 sure is better than $$$$$ for a new motor. I can't even guess what a new motor costs.
$2100 to rebuild your might end up closer to $2600 when your mechanic finds that something else is wrong or cracked.

Just for info, check into Outboard Exchange in Waterford CT. They might have a used or rebuilt lower unit on hand.

 

[freddy063]

check the bushing it's a 40 $ part,it's on the shaft of the lower unit in the bottom of the motor, my bushing seazed and it acted the same way yours did, I fixed it for total 52 bucks. You will know when you remove the lower unit if it wouldn't come off that the bushing is stuck on the shaft. and I see lower units on lone for that motor new around $ 800

 

[boslaw]

insurance surveyor said that the gearbox was completely shot when they pulled the lower unit. Lack of lower unit oil, although I still can't figure out how that happened. I filled it this winter, and they said the oil fill screws were both still firmly in place. I never noticed any slicks from leaks.