'86 200hp vro

Joined
Jan 11, 2008
Messages
8
can i use a vro pump from a '92 90hp on my '86 200hp without running lean. reason i'm asking is because someone took off the original vro, and put one standard fuel pump on. runs like crap. i know running standard lift type fuel pump,a 200hp needs two pumps. just wondering if the 90hp vro will work only to check to see if this is the problem before i spend $400 on a new vro pump. i pre mix, so the oil pump part i don't care about. just don't want to run lean during testing.(low fuel flow rate.)
thanks for your help
mike
 
Joined
Jan 11, 2008
Messages
8
Re: '86 200hp vro

thanks ezeke.
i installed the vro. now i get between 3.5-4.5 psi of fuel pressure. i have 2 temp clear lines, one after the primer bulb, one after the pump. i see no bubbles on the suction side, but the pressure side doesn't fill up. i do see fuel flowing. is it normal for the pump to cycle, pressure goes down to 3.5 then clicks, and pressure goes up to 4.5 psi. continuously doing this pattern.
 

ezeke

Supreme Mariner
Joined
Sep 19, 2003
Messages
12,532
Re: '86 200hp vro

The presure cycle is correct. The pump is considered good as long as pressure does not drop below 3 psi at 800 RPM with the gauge level with the output fitting. Your system may have an air leak at some point on the input side, on the pump membrane or on the oil side, however the pump may not clear air already in the output line. The fuel input line should test below 4 inches Hg and have no air bubbles.
 
Joined
Jan 11, 2008
Messages
8
Re: '86 200hp vro

found the problem, was the tee i used to test fuel pressure, it was a cheap plastic type for vacuum on cars. went to lowes a made a nice brass one with 3/8 fittings. much better. the plastic one only had a 3/32 inside diameter. seems to run much better with the vro.
thanks again.
 
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