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I blew up my yamaha zx250. The while power head needs to be replaced. Is it better to rebuild it or buy a used motor? I am seeing some pretty good deals online for newer motors.

Just trying to get opinions.
 

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How do you blow a power head? Not trying to be a smart ass just want to take care of the engine I have now. Avoiding pitfalls or other peoples past mistakes will help me avoid costly bills I can't afford. Thanks!
 

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How do you blow a power head? Not trying to be a smart ass just want to take care of the engine I have now. Avoiding pitfalls or other peoples past mistakes will help me avoid costly bills I can't afford. Thanks!
I hate to say it but it is not a matter of if, but when will a powerhead blow. Some motors blow at 100 hours, some motors blow at 5,000 hours. Basically, powerheads blow when something causes one of the pistons to freeze up and the resulting built up pressure causes it to crack the head.

The three main things you can do are:

1. Keep up with routine maintenance and have your boat serviced at least once a year so that it can be reviewed by a qualified mechanic for any issues that might result in engine failure.
2. Use the boat as often as you can. When things sit, they can corrode and/or deteriorate (think fuel lines).
3. Always fill up with high quality gas at busy gas stations. Either keep your boat full of gas or only put in as much gas as you will need for that fishing day. I always run my boat to darn near empty and then fill it up with fresh gas when I use it. Treat your fuel for ethanol as recommeded by the manufacturer of your motor.

Hope this helps.
 

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I drove the boat a week before it blew. Something was definitely off with the motor. It felt like it was not running on all six cylinders. When the motor blew, you could see clear through the crankcase. From the photos of the heads it was most likely cylinder detonation.
 

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I drove the boat a week before it blew. Something was definitely off with the motor. It felt like it was not running on all six cylinders. When the motor blew, you could see clear through the crankcase. From the photos of the heads it was most likely cylinder detonation.
Ding. Ding. If I am understanding you correctly, you ran the motor, something felt off but you continued the run the motor until it blew? Not to get preachy, but big cause of outboard failure is to ignore the signs. When it doesn't feel or sound right, don't run it.

As far as build vs buy used each situation is different. Personally I wouldn't buy a used outboard unless it either A)came from a reputable shop or B)allow a mechanic to perform full diagnostic and leak down tests. If rebuilt you have to find root cause, otherwise you are just throwing parts at it and she will come apart again on you.

Also look at getting a fully dressed reman power head. I can't remember the name but there are several aftermarket companies that will sell you one for about the same price as rebuilding the old one. It's another option to consider.

Either way, sorry to hear about it. i have been there a few times. I know this sounds like an old man but I am a firm believer that an outboard will stay together much longer if you do 3 things. 1)Let it warm up, it takes longer than you think. 2)Stay out of the gas and off the rev limiter. The guys that know two speeds (idle and WFO)seem to have the most problems. 3)Find a good shop and perform, by the book, routine maintenance
 

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Tdub. It's not my boat. I drove it for less than 10 minutes and told the owner that it didn't feel right. We stopped by the marine shop on the way home to get new plugs, but they didn't have any.
 

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Tdub. Good advise on how to run the motor. I don't hit the lower WOT for at least 15 minutes on the morning. Rarely do I push my motor to the high WOT limit. You are right about people knowing only two speeds. It's an expensive lesson.
 

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Tdub. Good advise on how to run the motor. I don't hit the lower WOT for at least 15 minutes on the morning. Rarely do I push my motor to the high WOT limit. You are right about people knowing only two speeds. It's an expensive lesson.[/QUO

How is the motor we rebuilt for you last year running?

We ...Tracker ATX rebuilt 8 or 9 Merc's last year with just 1 repeat failure and we took care of the customer and had him back on the water in a week or so. Rebuilds can save some money depending on the severity of the failure. If the block is windowed it's less expensive to get a re manufactured rotating assembly. Regardless of which way you go the root cause of the failure must be identified to avoid a repeat. Fuel injectors, air injectors and oil pumps and so on must be serviced.

I currently have a 250 Pro Xs rebuilt with new rings , bearings and one new piston. Fuel and air injectors have been serviced as well. This is a drop on and could be installed and running in a couple of hours. This is a power head that I built as a spare for me but will sell if someone needs it. This motor is on a stand and can be run if you would like to see it.

DO NOT FORGET TO DETERMINE THE ROOT CAUSE......
 

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I second Texas Outboard rebuild, I took my Yamaha there when mime blew and they have there own machine shop plus a 4 year warranty. I drove it up there and it save me 5 grand from any where else. have not had a problem in the last 2 years so I am very happy with them.
 

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I would say when you buy used 70% of the time you are buying someone else problems, I would have it checked out before buying a used motor for sure. I just bought a parts motor last week to fix my motor with and wouldn't you know the part I needed was bad as well. Now I am ordering new parts to get on the water, only good thing about my situation is I have a lot of spare parts
 

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Either way, sorry to hear about it. i have been there a few times. I know this sounds like an old man but I am a firm believer that an outboard will stay together much longer if you do 3 things. 1)Let it warm up, it takes longer than you think. 2)Stay out of the gas and off the rev limiter. The guys that know two speeds (idle and WFO)seem to have the most problems. 3)Find a good shop and perform, by the book, routine maintenance
Tdub. Good advise on how to run the motor. I don't hit the lower WOT for at least 15 minutes on the morning. Rarely do I push my motor to the high WOT limit. You are right about people knowing only two speeds. It's an expensive lesson.
What's a good general recommendation for how hard to run a motor? During the first hour of the break in period on mine, the manual recommended keeping the RPMs between 4000 RPM and 5750 RPM with RPM changes at least once every two minutes.

Here's the Mercury Boat House Bulletin for it. Now that I'm finished with the break in period, how hard would you run it?

https://www.mercurymarine.com/en/br/performance-tests/bhb/5444/?units=imperial
 

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It depends on the motor. My WOT is 5800. I never run it that hard for more than 2 minutes. I usually cruise around 5500, which is just below high WOT.
 

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Wot for extended periods is okay as long as the motor is in good condition and has good fuel. Most anglers do not follow good heat sink procedures. I have witnessed many motors go from off trailer to wot as soon as they get out of the no wake zone. If you have and watch a SmartCraft gauge you can watch the thermostats open and close which can take more than a few minutes depending on water temp. Proper warm up and cool down can add years and hours of operation to a motor. Aluminum pistons and steel cylinder sleeves expand and shrink at different temps and should be considered when shutting the motor down after long runs. Let it idle for 3 or 4 minutes before killing it.
 
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