89 200hp rebuild

[JonLewis]

I have an '89 200 hp evinrude that has low compression in all cylinders (55-60) psi. I did try and decarb the motor but it didnt help with the compression. I was wondering what all is normally done in a rebuild on an outboard. I realize that you will never know forsure untill it is appart, but there has to be a norm for this. My second question is if I am going to tear this thing down, are there any performance/durability upgrades that can be done. I have rebuilt many car motors, so should this be attemped by someone with my limited experience? thanks

 

[Walker]

Re: 89 200hp rebuild

First thing I'd do is another compression test with a different guage. <br />Is the motor hard to start?

 

[JonLewis]

Re: 89 200hp rebuild

It has been pretty hard to start when cold but warm starts arent too bad. At the beginning of the year compression was about 85 psi in all cylinders so I thought that it was just a matter of time. The last time that I took it out it had absolutely no power. It would not get over 15 mph or so. I will try another gauge and let you know.

 

[JonLewis]

Re: 89 200hp rebuild

I checked the compression with a different tester and cam up with numbers that are in line with the previous. I also did a wet compression test and the numbers increased dramatically. In my mind this tells me that the rings are just worn out. Is this line of thinking correct? thanks

 

[Dhadley]

Re: 89 200hp rebuild

I'd suggest we pull the heads and take a peak. They gotta come off sometime. <br /><br />Its odd that your compression went downhill that fast, especially after a decarb. Anyway lets have a look-see and go from there.<br /><br />As far as up-grades -- yes there is something you can do while youre in there that dramatically improves the running of that motor. Especially the idle. Its no big deal and is easy. We'll get into that later. Lets just get the heads off for now.

 

[JonLewis]

Re: 89 200hp rebuild

Well I took the heads off to take a look but nothing jumps out at me. The head its self is very clean with no carbon build up. The cylinder walls dont look to bad, they look to show normal wear and there isnt alot of ridge build up at the top of the cylinder. To me, there doesnt seem to be evidence of broken rings. The pistons themselves have some carbon build up although I am not sure how much is normal. What else should I look for?

 

[Dhadley]

Re: 89 200hp rebuild

Is it possible to post some pictures? <br /><br />If it looks that good I'd put the heads back on and do another decarb. Doing the "wet" compression test indicates the rings might still be stuck. I've seen motors that took 3 decarbs to get things going the right direction.<br /><br />You didnt mention anything about the head gaskets or surfaces so we assume those looked good too.<br /><br />Tell us a bit about the set up. Whats the top rpm with an average load? Champion plugs, right?

 

[JonLewis]

Re: 89 200hp rebuild

The boat is a 1989 Stratos 201 pro (20' and a few inches) and does have a Jack plate on it although I will have to measure to find out what size. The motor has a 4 blade 25 pitch ss prop on it. the boat has not performed as well as I thought that it should. It does not get onto plane very fast at all and tops out at 56 with 2 people in it at 5500 rpm. the last few times out it seemed worse and finally just wouldnt go much at all really. It really takes some adjusting of the trim to get anywhere near 5500 rpm and most times it wont get to 5500. I have done some adjusting of the jackplate but always end up where it was originally.I do have some pics but do not know how to post them. I can email them if I can get some email addresses. All of the interest and help is appreciated. And I have run both of the plugs that evinrude suggests, the regular and the gapless.

 

[Dhadley]

Re: 89 200hp rebuild

5500 is OK but minimal. We'd like to see that motor at lot closer to 6000. Even more wont hurt. At a top rpm of 5500 and a 25 4 blade, we're not surprised the holeshot is lacking. <br /><br />What brand / type 4 blade is it and have you tried anything different?<br /><br />We're kinda at a crossroad. We can put the heads back on and try another decarb (I'd really like to see you use the OMC/BRP Engine Tuner) or just go ahead and tear into it.<br /><br />If you want to you can send the pics to dhadley50@aol.com.

 

[JonLewis]

Re: 89 200hp rebuild

I will get those pics to you hopefully tonight. The decarb that I did was with the Evinrude engine tuner and a gas adative. I dont have them in front of me so I will check the exact names of both and let you know. They were both omc products. I would like for you to take a look at the pistons/cylinders and give me your opinion. thanks...Jon

 

[JonLewis]

Re: 89 200hp rebuild

Well I finally got the motor torn down. 1 cylinder was scored pretty good but the other look very good. The machine shop guy thinks that he will be able to get away with just a hone on 5 of the 6 but he advises to replace all pistons. Do you guys have any other advise about this rebuild? Dhadley, can you advise me of the modification you mentioned in this post? The help is always appreciated.

 

[Dhadley]

Re: 89 200hp rebuild

Doesn't sound like he measured the block, just looked at it. That's OK, lets look at it this way --<br /><br />The expensive part of any rebuild, parts-wise, are the pistons. He wants you to buy all 6. Boring is not all that expensive so why not bore all 6 if you're gonna spend the $$$ on pistons anyway??<br /><br />Following the thought of all new pistons -- use the 1993 & newer pistons. They're much lighter. You could even use the newer, lighter rods. You won't believe the difference in the idle.

 

[JonLewis]

Re: 89 200hp rebuild

The machine shop told me that one cylinder would have to be bored to the max, I think that he said 60 over. So should I just bore the others to 20 and the 1 to 60. I heard that this is ok to do on an outboard. If I dont have to buy rods, will the newer pistons still work? Are there any other modifications that have to be made for the newer style pistons?

 

[Dhadley]

Re: 89 200hp rebuild

Where is he going to get a .060 over piston?

 

[reeldutch]

Re: 89 200hp rebuild

my advice is find a machine shop who will provide you with the pistons.<br /><br /><br />i agree with Dhadley if you buy 6 new pistons i would rebore the whole block. no sence to put new pistons in old bore.<br /><br />but if the pistons are still in spec i would only buy 1 oversized piston and rering the old ones.<br />you will save about 700 dollars.5 pistons and 5 rebored cylinders.<br /><br />but be shure you find a good machine shop who rebore these outboards.<br /><br />good luck sound like a fun project

 

[JonLewis]

Re: 89 200hp rebuild

I touched base with him agian just to make sure. It will be 40 over on 1 cylinder and 20 on the rest. The machine shop does do alot of outboard work so I dont think that will be an issue. I will make sure about the pistons, I dont want to spend any more than I have to but I also dont want to take any chances. So these pistons will work on the existing rods?

 

[reeldutch]

Re: 89 200hp rebuild

you cant go wrong if you get all new pistons and rebore all 6 cylinders.<br />probbebly the best way to go.<br />more $$$ but.... piece of mind.<br /><br />yes the new pistons will fit on existing rods.<br />make shure you have them all numbered with the bearings from the same rod.<br />i trow them in a ziplock bagg.<br /><br />cyl 1 -----rod 1 + bearings and caps<br />cyl 2 -----rod 2 + bearings and caps<br />etc etc<br /><br />you dont want to mix this stuff up because it will not interchange.<br /><br />but read the manual and when you are done reading it read it once more so you know what you are doing.<br />we can help you ,but a manual is a must.<br /><br />if you decide using the old pistons make good mesurements of pistons and cylinders.<br />be 100% shure there ok.<br />dont take any chances.<br /><br />good luck

 

[JonLewis]

Re: 89 200hp rebuild

I really appreciate the help. I have a clymber? manual but for a rebuild it didnt seam very good. So the guy at the boat shop let us borrow his evinrude manual-it is a little better. If there are any questionable or borderline parts, I will replace them. I have the money to do this right not twice. Again thanks for the help. I am sure that I will have more questions when the reassembly starts....Jon

 

[reeldutch]

Re: 89 200hp rebuild

you have any idea why it happend??<br />i would find that out before you will get a repeat and loose all the work.<br />remember a scored piston is a result of an other system failure.<br />make shure you find and correct the problem.<br /><br />good luck and send Dhadley those pics.<br />he can tell you or steer you into the right direction finding the problem.

 

[JonLewis]

Re: 89 200hp rebuild

would one of you guys happen to have the oem part number for a 20 over piston and a 40 over piston in the new style (1993 and newer)? I am looking for the one that has the rings, bearings, circlips and whatnot. I am not sure what all is included, I was told that it is easier to order this way. As always, your help is appreciated...Jon