Looking at a boat with twin 05 250s. One midsection was replaced and some corrosion was noted on the powerhead. What’s the expected life of the motor moving forward?
Yamaha 250 Block Corrosion
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Billv
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Not intending to be funny but short. Once the corrosion starts the engine will fail eventually. I learned the hard way
Looking for anyone who’s been thru this and an estimated timeframe to expect failure. Has anyone welded the powerhead with success?
The funny thing is that one motor can have corrosion but the other has none. I mention that because you didn't specifically mention the other motor.
It is hard to sat what life is left without knowing the extent of the corrosion and the corrosion if any in the second engine.
If the lower oil pan has corrosion, failure mode is near and often catastrophic. What tools or procedures were used to inspect the motors?
Personally I would pass on the boat unless it was priced like it had no engines, Even then, a repower may be not in your budget.
It is hard to sat what life is left without knowing the extent of the corrosion and the corrosion if any in the second engine.
If the lower oil pan has corrosion, failure mode is near and often catastrophic. What tools or procedures were used to inspect the motors?
Personally I would pass on the boat unless it was priced like it had no engines, Even then, a repower may be not in your budget.
There's really no way to give an accurate estimate. But we can at least offer better ideas if you provide much more detail and multiple pictures about what "some corrosion" means. Plus, the way you make it sound, it seems like the corrosion is on the outside of the powerhead... so... clean it off
Ekea
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The exhaust was replaced and there was corrosion on the block near the mating surface. Only have a pic of the upper leg:My 2006 250s were just replaced due to block failure on one due to corrosion. Installed New 300. They Had 1800 hours and ran great until one didn't.
Original It spent good part of its life being towed behind a yacht. Not a lot of flushing going on
Mobile marine mechanic here. Dennis is right that pictures matter. While you gather them, here is how I would size up a used pair before putting money down:
1. Ask why the midsection was replaced. A bent or corroded midsection can mean a hard hit, or long-term water intrusion. Get the answer in writing if you can.
2. Surface corrosion on the powerhead exterior is usually cosmetic. Corrosion where the block meets the exhaust adapter, around the water jacket covers or at the head gasket line is different, because that points at cooling system leaks. Look for weeping, white or green crust, and stained bolt heads.
3. Compression test every cylinder on both motors, warm. A leak-down test on any cylinder that is low or uneven tells you if it is rings or valves.
4. On the sea trial, check the tell-tale stream is strong on both motors, watch the temperature gauge for a full run, and look for steam from either exhaust.
5. Pull the lower unit drain plugs and look at the gear oil. Milky or metallic means a seal or gear problem.
6. Ask for service history, especially impeller, thermostat and oil change records.
7. If one motor is clearly worse than the other, negotiate hard. A mismatched pair costs real money.
If you can, pay a marine tech for a half-day check of both motors. It is cheap next to a powerhead.
General info only. Always follow your manufacturer's service manual.
1. Ask why the midsection was replaced. A bent or corroded midsection can mean a hard hit, or long-term water intrusion. Get the answer in writing if you can.
2. Surface corrosion on the powerhead exterior is usually cosmetic. Corrosion where the block meets the exhaust adapter, around the water jacket covers or at the head gasket line is different, because that points at cooling system leaks. Look for weeping, white or green crust, and stained bolt heads.
3. Compression test every cylinder on both motors, warm. A leak-down test on any cylinder that is low or uneven tells you if it is rings or valves.
4. On the sea trial, check the tell-tale stream is strong on both motors, watch the temperature gauge for a full run, and look for steam from either exhaust.
5. Pull the lower unit drain plugs and look at the gear oil. Milky or metallic means a seal or gear problem.
6. Ask for service history, especially impeller, thermostat and oil change records.
7. If one motor is clearly worse than the other, negotiate hard. A mismatched pair costs real money.
If you can, pay a marine tech for a half-day check of both motors. It is cheap next to a powerhead.
General info only. Always follow your manufacturer's service manual.
Boat in question was up for sale in the beginning of the summer and then pulled. My guess is the prospective buyer found mid section issues and backed out.
One motor received a new mid section and the boat was put back up for sale recently. I was able to speak to the mechanic (info given by the seller who’s been transparent) and he informed me of the corrosion on the powerhead mating surface (and he also noted the second mid section had earlier stages of corrosion upon inspection 1 year ago).
Just trying to estimate the life left in the motor from anyone who may have had the same issue. I know it’s just a guess at this point.
Ultimately the goal is to place a value on the vessel with the sick but currently functioning motors.
One motor received a new mid section and the boat was put back up for sale recently. I was able to speak to the mechanic (info given by the seller who’s been transparent) and he informed me of the corrosion on the powerhead mating surface (and he also noted the second mid section had earlier stages of corrosion upon inspection 1 year ago).
Just trying to estimate the life left in the motor from anyone who may have had the same issue. I know it’s just a guess at this point.
Ultimately the goal is to place a value on the vessel with the sick but currently functioning motors.
