'87 90 Evinrude Fuel and Oil problems (Long)

[onebohemian]

I have a 1987 Evinrude 90 horse V-4, E90TLCUR. Last time on the water, she'd get the boat up on plane but then cut out. Fuel bulb wasn't hard so I pumped it back up. Went for plane and again she would drop off, losing power but stay idling. Figured maybe I was running out of gas as my guage was showing pretty low so I pulled the boat out of the water and went home.<br /><br />Boat sat for about a week. I filled tank full and started boat on muffs in the driveway. Even at idle, she'll start to sputter after a few minutes of running. The bulb goes soft and when I pump it, the motor clearly picks up rpms. I opened the gas tank cap to make sure there wasn't a vaccuum in the tank, but it didn't help at all. Adding insult to injury, however, the VRO low/no oil warning horn started to beep as she sat in the driveway idling. I shut her down, pushed the boat back in the garage, and went in for a beer. <br /><br />I've read through both my Seloc and OMC manuals and other emails on this board discussing VRO, and although I think I have a pretty good understanding of how the VRO pump works, I'm still at a loss on a couple of points: <br /><br />1.) Is the VRO pump really two separate pumps? In other words, is there a fuel pump and a separate oil pump both built into the VRO unit? If so, can one go bad but not the other (or how could they both go bad at almost the same time)? <br /><br />2.) If the VRO is really only one pump that sucks both gas and oil from separate reservoirs and then creates the mixture before sending the gas/oil to the carbs, why wouldn't I have gotten the low/no oil alarm when I was out on the water with the boat?<br /><br />3.) Is there some type of pulse valve (can't really remember the name used in the manuals) that can be cleaned periodically and could be the cause of my problems?<br /><br />4.) There is a test described in the manual in which I would use a satellite tank with 50:1 mix connected directly to the VRO gas inlet. With a piece of clear hose attached to the VRO oil outlet and the hose marked in 1/2 inch increments and filled with oil, I can apparently check whether the pump is actual sucking in oil. This test doesn't strike me as being too helpful since I have both an oil and fuel starvation issue here (I think). Is there a test I can perform to test the entire VRO pump, oil and fuel suction?<br /><br />5.) Any other thoughts I what I might check or do? I'm not in too big of a hurry as the summer is effectively over for me as my wife is about to have twins any day. I think I was able to run enough fresh fuel and stabilizer into the motor before the low/no oil alarm went off so she'll be good for the winter. Changed the lower unit oil and fogged the cylinders through the spark plug holes as well. At least I know the cylinders have oil in them from the fogging even though she was beeping at me when I shut her down. If I need a VRO pump, where's the best place to shop for one (i.e., cheapest price)? I'm not sure yet whether I want to eliminate VRO or not. (To the extent I can help it, I don't want this post to turn into a debate about bypassing VRO as I've read all the past posts regarding that already).<br /><br />Thanks in advance,<br /><br />Can't wait to be ice fishing in the great north, <br /><br />Mark<br />Minneapolis, MN

 

[ob]

Re: '87 90 Evinrude Fuel and Oil problems (Long)

If your fuel tank is venting properly ,as it sounds like it is from your post ,and the fuel connections are good and leak free,I think you simply have a defective VRO pump since you can get the engine to respond by pumping the fuel primer bulb.<br /><br />The VRO pump indeed has a fuel and oil half that is driven by a common air motor via crankcase vacuum and pressure pulses.The fuel half draws from the fuel tank and the oil half draws from the oil reservoir.You can disconnectthe outlet hose of the VRO pump and route into a container while cranking engine to verify some flow but the best test is the one you already performed.A water test.And it sounds to me as if the pump is not keeping up with the throttle demand.Possible causes are fractured or worn air motor diapragm,worn fuel piston,leaky pulse hose from crankcase to air motor nipple,etc..New pumps or rebuild kits can be got.<br /><br />This is assuming that the problem of fuel delivery is not carb float related and that if the fuel bulb was pumped continually underway ,you could keep the engine up to throttle setting.In any case , good luck.

 

[Solittle]

Re: '87 90 Evinrude Fuel and Oil problems (Long)

I won't post here as you ahve already read about eliminating the VRO on 17 year old motors as I did on my 1987 110s. Remember I did not post here.

 

[onebohemian]

Re: '87 90 Evinrude Fuel and Oil problems (Long)

O.k., it's time for me to tear into this as spring will be here in a few months. Details of my VRO problems are in posts below. The reasons for today's post is I need to know what next?<br /><br />1.) Should I order a fuel pump (VRO) kit? I hate to just throw new parts at this in trial and error fashion but will do so if there's no other way to diagnose and fix.<br /><br />2.) Should I order a new VRO pump instead of the kit? Anyone know whether the kit comes with the fuel piston? If not, and that turns out to be my problem, it seems to me I should isntead throw the kit money at a new pump? Any other reason why I'd want a whole new pump instead of just a kit?<br /><br />3.) Once I've either replaced the kit or the pump, is it true I won't know whether I've fixed the problem until I start her up this spring?<br /><br />4.) Would a repair shop actually in the end save me money because they have the diagnostic equipment to pinpoint the problem and only fix it instead of my trial and error method?<br /><br />5.) I've got a full tank of gas (in the built-in fuel tank) for winter. I'm going to have to drain the whole tank and then put in a 50:1 mix to be safe regardless of who or how I attempt to fix this, aren't I?<br /><br />Thanks, <br /><br />Mark<br />Minneapolis, MN