1990 Evinrude 200 HP

[RetNav]

I have a pair of these engines on the back of a 256 WAC Dusky. Both engines run pretty good. The Starboard motor will turn 6000 rpms at full throttle. The Port engine will only turn 5200 at full throttle. The starboard engine was overhauled (powerhead) last year. The compression on the port engine is from 95 to 97. According to the timing light it is hitting on all six, the jets on both motors is the same, 62D, 42, & 46. Both tachs are set the same and the port tack is new. The props are a matched set, counter rotation. Does anyone have any idea as to what I could check?<br />.<br />I have been thinking about rigging a switch where I could make each motor read out on the same tach to eliminate any possibility of an error in the tach head. Worthwhile or not? <br />.<br />I have been fighting this for a year. Mechanic says nothing is wrong with port motor which leaves me with the question, Why won't it come up to top rpms as quick as starboard or top out around the same rpms? Help

 

[R.Johnson]

Re: 1990 Evinrude 200 HP

Have you ever checked compression on both engines to see how they compare? I would check both engines with the same tach, I would think this would give you a more accurate comparison.

 

[RetNav]

Re: 1990 Evinrude 200 HP

R.Johnson, Yes, the starboard engine (powerhead rebuild) reads 100-102 on all cylinders.<br />I am going to the gulf next weekend so I will go ahead and rig up a switch to put the output for the tachs, by way of the switch to the same tach head. Will post the results.

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Whats the timing set at on the port motor?<br /><br />Did they ever run the same?

 

[RetNav]

Re: 1990 Evinrude 200 HP

Dhadley,<br /> Both are set to 18 degrees. They have never run the same, the port motor has always been slower to come up in revs and won't top out the same. Have tried another set of props, different manufacturer but same results.

 

[RetNav]

Re: 1990 Evinrude 200 HP

bump

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Look at the carb throttle plates. You may have to remove the airbox to see everything. With the throttle at wide open, not running naturally, the throttle plates should be almost centered open. There is a connector at each bottom carb body. The top 2 open together and the connector opens each bottom one. If those bottom 2 arent opening it may act just like you describe. <br /><br />Dont run the motor under a load with the cover off.

 

[RetNav]

Re: 1990 Evinrude 200 HP

Dhadley,<br /> If I am reading you correctly, all carb plates should be centered open and approximately the same.

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Yep, exactly. Those bottom 2 are easy to get out of sync. It may not be that easy but we have to start with the basics. Youve done a good job so far with the compression and timing.<br /><br />By any odd chance do any of the plugs on that motor look different in any way?

 

[RetNav]

Re: 1990 Evinrude 200 HP

I just changed the plugs, gapped new ones to about 38 and all the old plugs had a tan appearance. Some a shade darker than others but not by much. It appeared that all were getting about the same amount of gas, spark, and combustion burn. <br /><br />BTW, Dhadley, did you see where I planed to rig a single pole double throw (on, off, on) switch so I could get a rpm reading on the same tach head? If so, is that a good idea or any chances of blowing a regulator/rectifier?

 

[Dhadley]

Re: 1990 Evinrude 200 HP

As long as you switch it with the motor off I dont see where it would hurt anything. It probably wont hurt if it is running but I wouldnt take a chance. Never thought about it before...<br /><br />Good news on the plugs all looking about the same. Which ones did you use?

 

[RetNav]

Re: 1990 Evinrude 200 HP

I am using Champion QL77JC4.<br /><br /> This might not mean anything but when starting them up cold I have to pump up the bulb and prime with switch a good bit on the starboard motor. Then it will fire right up. If you do the same with the port motor (the one with reduced top rpm) it will flood out. Plugs will be soaked and I have to either replace or remove and blow dry before attempting to start again. If not that then wait for a couple of hours and hit the key without doing anything to the bulb or prime switch.

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Interesting...the usual proceedure is to pump the bulb, turn the key to "On" and push the key in for about a 5 count. Then engage the starter. <br /><br />If the port motor floods that easy, it may indeed have something to do with it.

 

[RetNav]

Re: 1990 Evinrude 200 HP

Dhadley, I have another question for you. When you align the motors should they toe in, out, or be aligned straight. Right now they are about 3/4 inch wider at the prop than at the front (toe out)?

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Wider at the prop is toe in. Think about your feet. Wider at the heel means the toes are closer together. <br /><br />3/4" toe in is a lot generally. We find that on a V bottom we like the toe in to be about 1/16" to 3/16". We've found that to be the best position for thrust and water pressure. Its something you can experiment with. At your X dimension on your hull with your style props (whatever that is) it may indeed be the best.

 

[RetNav]

Re: 1990 Evinrude 200 HP

Dhadley,<br /><br /> I really appreciate all the information and you hanging in with me on this. I will get all mentioned checked/adjusted and post back the results. Hopefully this will cure what has been ailing this rig.

 

[Dhadley]

Re: 1990 Evinrude 200 HP

Lets hope we can get to the bottom of the low/slow rpm deal. We'll just take it one step at a time.

 

[RetNav]

Re: 1990 Evinrude 200 HP

Dhadley,<br /><br /> I found a leak at the engine side of the primer bulb. I figure if it leaks it probably allows the engine to suck air. What effect might this have on top rpm?

 

[Dhadley]

Re: 1990 Evinrude 200 HP

It may have some effect. Even if the rpm's stay the same, sucking air is not good.<br /><br />Good find!