VRO pump issue or something I am overlooking?

[jwronkow]

I have a 1990 Evinrude 150 with a VRO2 pump. The engine was rebuilt last year and running great. Just lately, I have been having an issue at high rpm 4900 - 5000, the engine will start to pulse. If I squeeze the fuel bulb the engine runs fine. I have changed the fuel bulb, checked the fuel lines and even put a portable tank to see if it was a fuel issue or tank issue. Still have same results at low to mid-range speed run all day. I even had to tow a boat in and ran at 2000 rpms under load for a while without having to pump the bulb. I was looking at the pulse limiter but don't know if that would be it. Not really sure what the full function of the limiter does. Are pumps either good or bad? It seems the pump runs fine even at high speeds 4900 - 5000 for a little while but then starts to act up after approximatly 6 or so miles and will act like that for the rest of the day. VRO2 pumps are expensive and I don't really want to spend the money if it isn't the cause. Any help or direction would be appreciated.

 

[rickdb1boat]

Re: VRO pump issue or something I am overlooking?

Take a good look at the pulse hose and make sure it is tight and there are no air leaks, as well as all the small lines to the carbs abd primer. Also, you should have the updated Blue pulse fitting on the limiter, not the black one...

 

[jwronkow]

Re: VRO pump issue or something I am overlooking?

I had to fix the hoses on the primers. One was cut and left fuel everywhere that is how I caught it. The issue was there before and after the primer hoses. The limiter has the black fitting and is in-line not screwed to the block. Limiter is only 25.89 and 335.00 for pump.

 

[alden135]

Re: VRO pump issue or something I am overlooking?

I have a great vro2 trouble check chart, but I'd have to email it to you as an attachment.

 

[alden135]

Re: VRO pump issue or something I am overlooking?

Let's see if this works.....

 

[reeldutch]

Re: VRO pump issue or something I am overlooking?

you might want to check the fuel pressure between the carbs and the VRO pump.
put a clear vynil hose and a vacuum gauge before the fuel pump.
run the motor to 5000 rpm and watch the fuel presure gauge.
also wach the vacuum gauge and hose for fuel vapor or airleak.

sometimes at higher rpm there is more vacuum and a little leak might open up to become a big leak.

if your fuel pressure is ok dont spent the money on a new vro pump.

actualy its not a bad idea to replace the pump but fix the problem first.

good luck

 

[jwronkow]

Re: VRO pump issue or something I am overlooking?

Let's see if this works.....

Alden,
Even after fixing the primer hoses and ensuring there were no leaks, I still have the issue. I haven't bought a new limiter yet but will look at replacing that next. Looks like the attachment didn't work. Can you email it to me at jwronkowski@gmail.com. --Thanks

 

[alden135]

Re: VRO pump issue or something I am overlooking?

Let's see if this works.....

Alden,
Even after fixing the primer hoses and ensuring there were no leaks, I still have the issue. I haven't bought a new limiter yet but will look at replacing that next. Looks like the attachment didn't work. Can you email it to me at jwronkowski@gmail.com. --Thanks

That chart is the file I was talking about.

 

[alden135]

Re: VRO pump issue or something I am overlooking?

Is it not showing up for you? Do you see the chart or a red x?

 

[rickdb1boat]

Re: VRO pump issue or something I am overlooking?

Big and bright for me....

 

[Salmonseeker]

Re: VRO pump issue or something I am overlooking?

I had a very similiar problem with a 2004 Johnson 50HP with a VRO. It would run great except at WOT which was at the time around 5000 RPM. At WOT the rpm's would go down about 1000 and then shoot back up repeating itself over and over again. At all other throttle settings it worked great. Pumping the bulb very fast stopped this. I was told to check all the things you were told to check. I spent about 3 weeks trying to figure it out. I finally got a Maintenance manual and went to the trouble shooting chart.

One suggestion was a clogged main jet in the carberator. I took apart the carbs and sure enough there was a blockage. There was a small piece of something blocking the jet in one of the carbs at the bottom of the fuel bowl. I Never found out what it was. It got blown out and lost somewhere. I cleaned the carb and put it back together. Ran perfect ever since.

I guess the restriction was not allowing enough fuel to fill the bowl required for WOT. So it would run out of fuel and begin to die, Then the bowl would get some more fuel and just repeat this procedure.

Not one person suggested I check this. Even a dealer told me I may have to replace my fuel pump. I am not saying this is your problem, but it was mine which was similiar to yours.

That is actually how I found this site. I am still amazed at the fast response time posts get here.

 

[reeldutch]

Re: VRO pump issue or something I am overlooking?

that is exactly the reason you should check the fuel presure from the vro to the carbs.
at wot.
if the fuel presure is ok there is a prblem after the fuel pump.

so you eliminated the expensive pump with a quick and simple test.

 

[jwronkow]

Re: VRO pump issue or something I am overlooking?

Thanks all for some great pointers. I didn't have a pressure gauge so I pulled the carbs to check them out. I didn't see anything glaring but cleaned the bowls and blew out the jets. This also let me check the smaller hoses and nipples behind the carbs? I also checked the manifolds and primer hoses more closesly. I didn't notice anything regarding the hoses or nipples. I will have to wait until this weekend to test if cleaning the carbs helped. If that fails then I will find a pressure gauge and go from there. Will let you know the outcome next week.

 

[jwronkow]

Re: VRO pump issue or something I am overlooking?

Update: I ended up replacing the pump and all worked great. It was still acting up after cleaning the carbs so I replaced the pump and took it for a long trip. Ran ~ 40 Miles at 5000 RPMs and didn't have an issue. Thanks all for the help.