Leaned out... Gasket blown?

[Bass treble]

I have a Suzuki/spirit DT65 from 1979 that I bought this spring. It has been running like a top, but today I forgot to open the air vent on the gas tank and the engine started to rev harder than normal at full throttle. I killed the throttle and saw that the vent was closed. Opened it up and fired it back up and kept it in neutral to keep water cycling to cool the engine. But I noticed there are now EXHAUST BUBBLES coming up in the water, although I don't think the bubbles are coming from the water intake... Not entirely sure though. The engine still spits water and exhaust as it should, but it seems as though there is less water being pumped the more you get on the throttle? Also, when I try to get it up to plane at full or near full throttle, it just doesn't have the power like it should and it starts to smoke/rev harder/exhaust more, but again, seems like the water isn't spraying from the exhaust port as hard... I hope this is clear enough. Any advice would be very appreciated. Thanks, BT from big sandy lake, MN

 

[Grub54891]

I wouldn't think that forgetting the fuel vent one time would hurt anything. Especially The cooling system. What you are noticing is more than likely normal for the motor. ​Sometimes when an individual has an issue, They pay more attention than they have in the past, I think that is what you are seeing.

 

[Bass treble]

Even leaning out at full throttle? My friend says it may have scored the Pistons causing some loss of compression and subsequent loss of power at the top end? Does that sound possible?

 

[flyingscott]

Is it pumping water and how does it run. People run out of gas all the time and it doesn't hurt the motor at all ,there is enough residual oil in the system to be fine . The bubbles are exhaust coming up probably from where the lower unit bolts on no big deal. I am pretty sure that is oil injected should be fine. If the oil injection is working the motor is still being lubed. Just make sure your waterpump has been replaced recently and enjoy your motor.

 

[Bass treble]

50:1 mix two stroke. It is pumping water but it seems like it pumps better when idling or at slow speeds, but it does pump all the time. I guess I'm more concerned with damaged Pistons or head gasket... It's really strange, though it seemed to be fine today when I drove it to trailer by myself. Granted, I only had one passenger yesterday when this all happened, but it wouldn't go above 15 or so mph and it would wind out hard like it sounded when the fuel cap was closed. Today I had it at 25mph at 3/4 throttle and the fastest it's ever done is 31. But with the age and rarity of this Arctic spirit/Suzuki it is extremely unlikely I could find hard parts for it. Guess I'll sail til it fails...

 

[99yam40]

If you are worried about the compression ,then test it.
someone on the web on a computer will not know what is wrong with your motor from forgetting to open the tank vent.

if you are worried about the water flow look into changing the water pump and stat

 

[flyingscott]

50:1 mix two stroke. It is pumping water but it seems like it pumps better when idling or at slow speeds, but it does pump all the time. I guess I'm more concerned with damaged Pistons or head gasket... It's really strange, though it seemed to be fine today when I drove it to trailer by myself. Granted, I only had one passenger yesterday when this all happened, but it wouldn't go above 15 or so mph and it would wind out hard like it sounded when the fuel cap was closed. Today I had it at 25mph at 3/4 throttle and the fastest it's ever done is 31. But with the age and rarity of this Arctic spirit/Suzuki it is extremely unlikely I could find hard parts for it. Guess I'll sail til it fails...

Check for a spun hub on the prop, take the prop off and scratch a line across the hub and next time it revs check the line see if it moves. A head or head gasket will not be damaged by forgetting to open the vent. Do you know how many people forget to open the vent on the gas tanks and never had a problem the odds are in your favor. A overheat will affect the head and/or head gasket. The revving for no reason sounds like a spun hub on a prop.

 

[Bass treble]

Check for a spun hub on the prop, take the prop off and scratch a line across the hub and next time it revs check the line see if it moves. A head or head gasket will not be damaged by forgetting to open the vent. Do you know how many people forget to open the vent on the gas tanks and never had a problem the odds are in your favor. A overheat will affect the head and/or head gasket. The revving for no reason sounds like a spun hub on a prop.

will do that... That seems to be exactly what is happening. I'll try to tighten that nut down if it is. I'm hoping that That's all it needs if so. I don't really have the tools to dig in any further. Thanks!

 

[Grub54891]

Tightening the nut wont help, the hub is usually a rubber insert, pressed or molded in to the prop itself. If it's slipping, it needs to be rebuilt or replaced.

 

[Bass treble]

Ok thank you! Looks like that wouldn't be that expensive at least for the part itself. If that hub is bad could it be letting water into the gearcase as well? Cracked the nut and the fluid is like elmer's glue

 

[Grub54891]

No the prop will not let water in to the gear case. If the lower unit lube looks like milky oil, or Elmer's glue, you have a leaky unit, it needs to be re-sealed before it causes any damage to the gears, if it hasn't already. At this point, I'd be taking to a good marine repair place, and have it done correctly. It does not seem like a job you can do yourself at this point. No offense intended.