1990 Evinrude 150 XP Compression #'s

[Spork]

Hello all, new member here. Having some problems with my engine and figured this was a good place to start.<br /><br />Here's what has happened so far. Motor will idle fine all day long, but if you give it power it will run fine and then all of a sudden it acts like somebody pulls the throttle back.<br /> <br />I had a mechanic look at it and the first thing he thought of was head gaskets after doing a compression test (all cylinders were mid 80s). Well he left that day and I started thinking about when the problem actually started happening and I realized it was right after the day that my son had left the oil cap off the oil tank and I had taken several large waves over the transom from a big boat wake and had got quite a bit of water. Anyway, I found out that I had water in the oil. When I pulled the oil hose from the engine to check, nothing but water came out.<br /><br />After disconnecting the VRO and removing and cleaning the carburetors it runs better, but it's still not right. I've taken it down to the ramp and left it on the trailer so I would have back pressure and it's still wanting to do the same thing about 3700 rpm. It will run for a short while and then act like somebody just pulls back the throttle, but it will continue running now (it wouldn't before). I checked the compression again today and all cylinders were in the mid 80's. Do I need a rebuild or would it be better to just buy a newer motor? Or could there be some other problem?

 

[Hooty]

Re: 1990 Evinrude 150 XP Compression #'s

Wow.<br />Nothing but water out the oil line, huh? That scared me and I'm fearless! What do the plugs look like? I'm not sure you could tell anything from looking at them anyway. That 80# compression sounds a mite low. I think I'd pull a head and see what the cylinders look like before I did anything else.<br />You got a shop manual for that thing? <br /><br />c/6<br />Hooty

 

[Hooty]

Re: 1990 Evinrude 150 XP Compression #'s

One more thing Spork, keep us informed, if ya would, about what ya find, etc. Just reply back on this same thread.<br />Thx.<br /><br />g'luck & c/6<br />Hooty

 

[OBJ]

Re: 1990 Evinrude 150 XP Compression #'s

"Fearless"?????? <br /><br />Spork...ya' did'nt say it but did you empty the VRO reservoir tank and clean it out to?<br /><br />And by the by since Mr. Hooty won't, I will give ya' the iboats greeting....WELCOME!! <br /><br />AWWWWW.....you'll grow ta' luv' us!!

 

[Spork]

Re: 1990 Evinrude 150 XP Compression #'s

No we didn't empty the VRO reservoir, and I was thinking the same thing. I know it's part of the fuel pump, maybe I can try that tomorrow. The mid 80's compression sounds low to me. But it seems to run fine at idle and at lower rpms. It could very well be water in still in the system somewhere. I've got a good mechanic that works for almost less than nothing on it, but he's out of town until Monday and I'm wanting to get this thing back on the water and get some fishing in. Doesn't look like the weather's going to cooperate anyway though.

 

[OBJ]

Re: 1990 Evinrude 150 XP Compression #'s

If the lid was left off, you got water in the reservoir. Oil floats on water so you may be sucking water. NOT GOOD. Before I would crank her up again, I would empty and clean out the reservoir and put a new filter sock on. I would also drain the carbs again and all oil hoses.<br /><br />(EDIT)You might try a decarb for the low compression. Might help.<br /><br />Keep us posted. Good Luck.

 

[Spork]

Re: 1990 Evinrude 150 XP Compression #'s

OBJ,<br />The VRO has been disconnected and I started mixing the oil with the gas. Maybe I'll have to take those carbs off again tomorrow and clean them up along with the fuel pump/VRO.<br /><br />I'm just wondering if mid 80s is normal for that motor. I checked the compression when it was cold too. Should I warm it up first?

 

[Hooty]

Re: 1990 Evinrude 150 XP Compression #'s

Usually, when you check compression, you aren't looking so much as what it is but how each cylinder compares to the other. If it's warm, it may come up a little but not much. I think I'd try OBJ's suggestion and decarb that puppy. Can't hurt a thing and may bring the compression up. Has it ever been decarbed? When?<br /><br />c/6<br />Hooty

 

[G DANE]

Re: 1990 Evinrude 150 XP Compression #'s

Spork<br /><br />Water left in the VRO oilmixerpump will end up in carbs. Water in carb bowls will restrict flow to your highspeed jets. Try to get all the water out of the system, eventually by letting the pump pump oil again, ( From a Clean oiltank ) with 1:50 premix in gas tank in same time. You will overoil, but it doesnt harm anything. Afterwards drain all your carbs. Do the decarb . Usually with serious compression problems, iddle will be affected. A lot af these run fine with compression around 90, I think they are lowcompression design. Someone correct mee if wrong. Do you know what you had before ? the decarb sugggestion is good, wouldnt hurt anything, usually lifts comp. #s.

 

[walleyehed]

Re: 1990 Evinrude 150 XP Compression #'s

I think if it was me, I'd pull the plugs and shoot some oil in the cylinders and spin'er thru, just in case there would be a tad bit of water hidin' inside....good idea on the 50:1 pre-mix in the tank too...might save you an engine until you know the VRO is working again.

 

[Spork]

Re: 1990 Evinrude 150 XP Compression #'s

Cool, thanks guys. The mechanic that looked at it last week didn't mention anything about the low compression. He just said it could possibly be head gaskets. This gives me some direction anyway. I'm getting kind of frustrated because I'm wanting to fish and don't want to put too much effort into this motor if it can't be saved.<br /><br />Hooty,<br />I decarbed it last year, but it was after I started having problems and I never pulled the plugs and sprayed decarb in there. I'm going to try that as well and see if it raises the compression at all.