powerhead rebuild standard procedure?

[GlasV162]

Hi all,
1990 90 hp Evinrude

Is it standard procedure to bore the cylinders when rebuilding the powerhead?
Thanks.

 

[ezeke]

Re: powerhead rebuild standard procedure?

When needed it is, but you just do the cylinders that require boring, not the ones that don't.

 

[emdsapmgr]

Re: powerhead rebuild standard procedure?

Sometimes it is a rebuild shop policy to do that, if they are providing you a warranty on their work.

 

[tashasdaddy]

Re: powerhead rebuild standard procedure?

personally, if i'm going to the trouble myself. i'm going all the way.

 

[R.Johnson]

Re: powerhead rebuild standard procedure?

The first thing to do is measure the bore, then you know what step's to take.

 

[david_r]

Re: powerhead rebuild standard procedure?

if you dont have all the proper tools for measuring the bore you can take your block and psitons along with your specs to a reputable machine shop and they should be able to tell you in no time if you need a bore or a re-sleeve if you lucky a new set of rings will fix ya up.

let us know how your project goes.

 

[mikesea]

Re: powerhead rebuild standard procedure?

simply,yes,otherwise your not rebuilding,as eng.hrs go on and on,your bore becomes out of round,the piston rings will wear to that shape in the cyl.if your eng was only a few hrs.old ,and for some reason you blew one cyl,you could probably rebuild the one cyl.and put each piston ,ring combo back it its corrosponding cyl.without any concern,but in your case,your eng.is over 18 yrs old,how many hrs.??? for that reason the right way to do it is reboring to the next oversize and put in new piston kits,new bearings and seals,you can then know your back to a new engine,at no point should you put new rings in without making the cyl round,doing so could reduce compression and give potential for broken rings,just thing round rings in an oval hole,be sure to have the ports checked for cracks between the ports,if there are cracks,you would need a sleeve,your crankshaft and rods are more than likely fine to reuse unless you had a catstrophic failure ,or sank and rust is an issue,be sure to rebuild your carbs during process,you dont want a lean condition,use new rod bolts

 

[GlasV162]

Re: powerhead rebuild standard procedure?

Hi,
Thanks for the input. I paid a shop to rebuild the powerhead almost 2 years ago and it hasn't run right ever since--it even locked up on me after just a few hours of running (see previous post). Out of frustration, I took the motor to another shop this fall; they said they would be able to tell very quickly after taking it apart what caused it to lock up and why it still isn't running right. Here's what they found:

1. One cylinder was bored; the other 3 weren't bored and were out of specs and out of round. New stock pistons, rings and bearings were put in.
2. Small plastic / rubber pieces that direct water flow around each cylinder weren't replaced. The one on the bottom starboard cylinder was restricting water flow, and that's the cylinder that locked up.
3. Block has been "decked."

The new shop told me that for a few extra bucks the first shop could've prevented the lockup by replacing those water deflector pieces, and it would've run a lot better if they had taken the time to bore all 4 cylinders. They (the new shop) also couldn't give me a decent reason as to why the block was decked. However, they told me the motor is definitely fixable, provided all 4 cylinders are bored (I think they said .0030 over) and they use low-compression head gaskets since the block has been decked.

The frustrating thing is this is going to run me about $1600.00 and I paid the first shop over $1800.00 and it sure appears it wasn't done right. Any advice?

 

[mikesea]

Re: powerhead rebuild standard procedure?

There really isnt much advice other than ,if,you are going to rebuild the almost 20 yr old motor again.Be sure the rest of the engine ,including the Trim and tilt,the lower unit including the alum.casing that hoising it is going to work for a couple seasons for ya.Be sure .the NEW rebuilder will bore each cyl to the next oversie which you say is 30 over.All bearings will be replaced,because for that price,which is right should include new bearings,gaskets,water deflectors that 1st guy left out,carbs rebuilt,filters changed,there should be NEW piston kits installed,not some used 30 over pistons that were laying around the shop with replacement rings.I worked for a few rebuilders.There are the guys that do it right,and those that dont.Be watchful of the 50/50 warranty guy.That means,if it blow ,you pay 50%.50% at retail can cost as much as the orig.job.Oh,and NEW parts should be ,NEW PARTS.Not used parts ,NEW to the eng.Meaning used.Your block,heads,crank and connecting rods will be reused.if their bad,it can cost you $$.Im sorry to say I've alot in the business.Most boaters dont know the mecanics.Then add to that %%%.What % of people use their boat alot.Take in consideration.Weekends only,you then have weather,illness,parties,vacation etc.So a warranty is good for how long?if you live where I live in South Fl.you may boat more than my friends in New England.If your a commercial guy.Some of the fly by nighters wont honor them ,it will be in the fine print.You likely got hosed by the first guy.He played the % game and won.You didn't bring it back.He made $$ and only fixed one cyl.Ive seen it.There are the guys that will fix the one cyl.BUT not charge you for a complete rebuild.Maybe 5-600.I am curious as to the state you live in,I know there are a few rebuilders,or should I say hosers in Fl.But I also know there are some great rebuilders.A wise shopper is a happy shopper.Good luck.

 

[Dhadley]

Re: powerhead rebuild standard procedure?

Advise? Sure. Stay with the new shop, sounds like they've got a handle on what's going on.

 

[GlasV162]

Re: powerhead rebuild standard procedure?

Since it's pretty clear that the first shop did a substandard / shortcut job, what are the chances of getting any money back from the first shop?

 

[Dhadley]

Re: powerhead rebuild standard procedure?

After 2 years? I guess if you've had some sort of ongoing issues that involved the first shop trying to fix them without success then maybe. But I would think thta your motor would have to have been an almost constant fixture at their shop. Or if you were in contact with them constantly at least.

The problem is going to be that if you had no contact with them for a period (depending on how the leagles see it) they would assume that the motor ran to your satisfaction.

You could just present the facts and see what they say, without mentioning lawyers naturally. Even if they offer to help with parts that's something. But that may offend the new shop too.

If there's a light at the end of the tunnel it may be a train.

 

[mikesea]

Re: powerhead rebuild standard procedure?

I hate being negative,the fact that they didn't do right by you from the beginning leaves me to think they are not likely to do you any good now.dehadly has said it already,time and your contact is important.Did you have ongoing contact.?What they may do,and I doubt you want to go there is offer you another rebuild,perhaps at a discount.But dont cont on anything for free.Even leagl stuff would probably be too late.If you try small claims and get a detail of new shops findings.

 

[Dhadley]

Re: powerhead rebuild standard procedure?

The term crossflow describes a style, like looper, Chevy big block, small block etc, rather than a system. The oil injection doesn't have lines other than the fuel in, oil in (to the pump), gas & oil out (to the carbs) and the pulse (operating) line. If he's talking about the recirculating lines, there are several ways to hook them up. Some earlier motors don't even have them.

There could be several reasons why there was excess oil internally.

 

[GlasV162]

Re: powerhead rebuild standard procedure?

Hi,
The second shop found another flaw in the first shop's "work." When he took the motor apart it was loaded with oil, and he discovered that the crossflow system had been messed up; I'm not sure how to describe it but it was something to do with oil lines not hooked up properly. Does this make sense?

 

[mikesea]

Re: powerhead rebuild standard procedure?

sure they did,they were incompetent,but,I would say that had nothing to do with the eng.failure.A Dhad explained,the guy is likely talking about recirc.lines.They supposedly have more than one purpose(Iwas told)they take unburned fuel,or fuel that gets caught up in the intake process and through timing ,other cylinders suck it up to burn.Preventing,DISCHARGE INTO WATERWAYS THRU EXHUST and?? ECONOMY.i CAN SEE WHERE ADDITIONAL OIL BUILDUP IS POSSIBLE IF THE RECIRC.LIES DIDNT GET EXCESS.BUT YOUR RECENT FAILURE WAS MOST LIKELY A POOR JOB INCLUDING LACK OF CORRECT MACHINE WORK,SORRY ,I HIT CAPS

 

[GlasV162]

Re: powerhead rebuild standard procedure?

Thanks. I just didn't understand the crossflow system, but with your help, now I do. The second shop showed me why the motor locked up in the first place--a water deflector that failed to direct water around the bottom starboard cylinder. In a nutshell, there are 4 things the first shop screwed up on:
1: They didn't bore the cylinders.
2: They didn't replace the water deflectors
3: Crossflow recirculation lines weren't connected properly.
4: Block was decked and they gave no explanation as to why they had to do that.

Thanks for the help guys.

 

[Dhadley]

Re: powerhead rebuild standard procedure?

Agreed, the first shop missed the mark bad. Especially on decking the block. That's going to be a big issue when determining the current rebuild.

Just to clarify - crossflow or looper describes how the fuel is introduced into the combustion chamber. There is no "system" - like an ignition or fuel delivery system - that in itself is a "crossflow system".

Just another point - in theory, the deflectors are supposed to be changed once a year.

 

[GlasV162]

Re: powerhead rebuild standard procedure?

Thanks. The second shop said that the "low-compression" head gaskets will correct the problem. I've asked in another thread if these work and I've had positive responses. I hope they work.

 

[Dhadley]

Re: powerhead rebuild standard procedure?

I'm impressed the shop knew about them. Good sign, stay with these folks (as mentioned). That will indeed resolve the issue or at least get you back close to stock.