Should I replace the Power head

[waterdowg]

I have an ‘89 Evinrude 88 spl. I melted the #3 piston on Fourth of July weekend. I went to a few Marina’s to see able getting it fixed. All said had to replace the power head, $2000.00 just to start plus any other parts needed but none of them looked at it just talked about it. There is no better way to justify a new boat to the wife. Now that I got brand new one. Now it is time to fix the old one. Two boats are better then one. <br /> I am not afraid to put in the wrench time, but have a few questions before I started. I have the Evinrude manual to refer to so here are my questions:<br />1. Do I need to replace the Power head? Or can I have it honed and sleeved<br />2. Can I just put in a new piston and rings?<br />3. Do I need to pull the power head off to remove the piston or can I do it still attached to the rest of the motor?<br />4. What other thing do I need to consider when doing this.<br />I think the melted piston was caused by a fuel problem, all the other are fine, but will find that out as well.<br /> Any help or advice would be greatly appreciated <br /><br /> Thanks Waterdowg

 

[gregpro50]

Re: Should I replace the Power head

I had an '86 Johnson 90 VRO same problem. Same estimate to fix it. After looking around I was able to fing a good 150HP motor for $1500. I ended up selling my old one on Ebay for about $650. (And the guy came to pick it up!!). All I am saying is that spending $850 for more HP and a good motor was better than spending over $2000 for a powerhead and then having to install it. Look around and see what you can find. Just make sure to check it out good.

 

[Dhadley]

Re: Should I replace the Power head

Sounds like typical coking damage. If the block is boreable (most likely it is) and the crank is good (if it still turns over it probably is) you should be able to get it completely done for the 2K. Including carbs cleaned and a new water pump. <br /><br />Usually if someone brings us a dressed V4 crossflow powerhead we can do it for 1600 to 1700 including boring and pistons. <br /><br />Good luck!

 

[Dhadley]

Re: Should I replace the Power head

Sounds like typical coking damage. If the block is boreable (most likely it is) and the crank is good (if it still turns over it probably is) you should be able to get it completely done for the 2K. Including carbs cleaned and a new water pump. <br /><br />Usually if someone brings us a dressed V4 crossflow powerhead we can do it for 1600 to 1700 including boring and pistons. <br /><br />Good luck!

 

[waterdowg]

Re: Should I replace the Power head

It still runs but only on 3 cylinders I think. If I pull off plug wires 2&4 it shuts down. If I pull off wire 1 it sputters it I pull off 3 it does nothing. I don't want to spend a lot of money. I want to do most of the work myself.

 

[Dhadley]

Re: Should I replace the Power head

Start with a compression check and if it verifies what we already know, pull the heads. We'll go from there.<br /><br />Get busy!! Lol!

 

[waterdowg]

Re: Should I replace the Power head

I didn't check the compression but I already pulled the head on 1 & 3. What should I look for. I will need to get a compression tester for 2 & 4.

 

[Dhadley]

Re: Should I replace the Power head

Dont worry about the compression test then. Describe what you see in #3.

 

[waterdowg]

Re: Should I replace the Power head

The surface of the #3 piston looks disintegrated. It looks nothing like the #1 piston. On the #3 spark plug had melted aluminum on the tip. The cylinder walls look smooth to the naked eye. I cannot guarantee that they are truly round with checking. The head also looked good. The pistons still move fine when I turn the engine by hand.

 

[Dhadley]

Re: Should I replace the Power head

Are the sharp edges rounded off of the top of the piston compared to number 1? Or is the edge of the piston eaten away right at the exhaust port?<br /><br />Either way Im suprised the cylinder head is not damaged. Usually thats a given. <br /><br />The most important thing is to find out what caused the damage. Keep in mind that the damaged piston is a result -- not a cause.<br /><br />Tell us more about how it was running and when was the last time you had it out before this happened. What fuel and spark plugs are you using? What RPM could it achieve before this?<br /><br />Let us know!

 

[JeremyC_Florida]

Re: Should I replace the Power head

I would spend a few bucks on a new piston.... and put it back together.... unless the other piston on the same side looks bad.. Sounds like you had a bad piston or a problem with it getting rid of heat around that cylinder... blocked cooling? or lack of exhaust exiting properly. Check your cooling ducts...

 

[waterdowg]

Re: Should I replace the Power head

The piston is eaten away. I did have a cooling problem at the beginning of the season but that was fixed before I put it in the water. I replaced the water pump, and thermostats and all was well. The last time I ran it before this problem, I noticed that the tach would stop working intermittently and the overheat alarm went off two or three times for about one minute then went off. I use to get about 4800 to 5200 rpm I think I can’t remember now that I have the new boat and has lower rpm range. What ever it was, it was were it was suppose to be at according to the manual. The day it went, the rpms were about 4500 and the over heat alarm had gone off about 10 min earlier and the tach had stopped working intermittently. The engine didn’t make any strange noise when it happened it just lost power but still ran. Also I just put in 5 gallons of fuel, at a 50:1 mixture that morning.

 

[JeremyC_Florida]

Re: Should I replace the Power head

Waterdowg ... you now know your problem... its the heat.. you can probably run that motor all day at lower RPMs and see the water coming out. But at higher RPMS the water must not be making through like it should. might not be due to the internal route of the water.. but it could be with the pickup side.. with the new water pump you are going to have to make sure at faster speeds and more RPMs its able to pull up the water... the heat sensor is letting you know cool water isnt getting through...

 

[waterdowg]

Re: Should I replace the Power head

If it was a heat proplem how will that affect if I need to do any work to the power head. Before I go and try to figure out why it happened I want to know if I can fix this with as little money spent as possible. It's just hard to spend $2000 to fix fix an engine when the boats oly worth $3000 with the motor and trailer.

 

[JeremyC_Florida]

Re: Should I replace the Power head

From what it sounds like, your powerhead is probably ok . (after replacing the damaged piston). look for a cooling issue... save your money...if the motor ran good before, the carbs and timing and all other factors should still be ok. you did say visually all other components look pretty good. As far as the tach jumping around ... thats just an electical issue with it most likely to be a bad connection. I'm taking it for granted that it wasnt misfiring and was still running somewhat smooth.

 

[thosch]

Re: Should I replace the Power head

I have a theory on the tach not working. It gets the signal from the rectifier/regulator mounted on top of the block (at least it is if you 88 is the same block as my 90). The regulator is cooled by bleeding heat into the block and cooling water. The regulator may be fried due to overheating. Is your pee hole line coming from the top of the block?

 

[waterdowg]

Re: Should I replace the Power head

Jeremy, It was running smooth and strong.<br />T.H., The pee hole is on the bottom of the block.<br /><br />As for removing the piston. Can I remove it with out taking the Power head off the rest of the motor. I have the manual but they tell you to remove the power head for just about every job. I would hate to remove the block if I don't have to.

 

[thosch]

Re: Should I replace the Power head

I believe that the powerhead must be removed, since the block must be split to remove the pistons. Some of the real experts around here (like Dhadley, and others) can give a definitive answer on that.<br /><br />My reason for asking about the source of the pee line is that a service bulletin was issued some years back regarding rerouting the line so that it comes from the starboard top of the block. That was to eliminate an air bubble in the top of the block, leading to overheating and regulator burnout. Dhadley can also comment more on that.

 

[JeremyC_Florida]

Re: Should I replace the Power head

t.h. is correct... gonna take a gasket kit to do this... and its a good idea to always have the pee line coming from out the top of the engine, that way you know that water getting through all of the engine, not just exiting the bottom... good luck

 

[waterdowg]

Re: Should I replace the Power head

Does anyone that service bulletin they can email. And I guess I will start taking it apart. I got a call into a local marine that sells used parts. Anything I should look for in buying a used piston. Are all four the same or are the different at each location.