havoc_squad
Senior Chief Petty Officer
- Joined
- Mar 5, 2011
- Messages
- 739
Looking at the parts diagram for a 1996 60 degree V4 115 HP model, the VRO style pump that has four, repeat four hose fittings is for the VRO pump that mixes oil and gas. (Fuel inlet, oil inlet, vacuum pulse, and outlet to vapor seperating Tank system.)
However, BRP does make a VRO style pump (almost just as expensive as the one that does the oil/gas mixing) that is pre-mix only that has only THREE hose fittings. (Inlet, Vacuum pulse, and Outlet to Vapor Seperating Tank system.
That is how you tell the difference between the VRO fuel pump that mixes the oil/gas and the VRO pump that does pre-mix only, by the number of hose inlets.
By the way, it's not very hard at all to do a fuel pump demand test on the lake. Just takes time to plumb in a T fitting between the fuel pump and the Vapor separating tank.
Extra fuel hose that is the size needed for the link between the fuel pump and VST.
Insert an appropriate T fitting of the same fuel hose diameter size.
Run a fuel line from that T fitting to the front of the outboard, then cap it off and clamp it down until you're ready to test the fuel pressure. Zip tie where appropriate to keep the hose manageable.
Buy a step down adapter that will join your T'd temporary hose at the front of the outboard to a vacuum/fuel gauge hose.
Use appropriate clamps to secure the fittings from leaks.
Now you got access to doing a fuel pressure test with the engine cowl off on the water, at load at speed. You'll just need a helper driving the boat while you monitor the fuel pressure gauge.
That may be overkill for your current circumstance if the service manual requires the following and your fuel pump/lines pass this:
1. You should have X inches Hg. of vacuum or less on the intake side of the fuel line/pump with no bubbles.
2. You have a stable X PSI at specified RPM level in gear, usually I believe that is about idle for most motors.
However, if you experience any symptoms of leaning out only when getting close to WOT RPMs, expect that a fuel pressure test on the water at speed may be the only route.
However, BRP does make a VRO style pump (almost just as expensive as the one that does the oil/gas mixing) that is pre-mix only that has only THREE hose fittings. (Inlet, Vacuum pulse, and Outlet to Vapor Seperating Tank system.
That is how you tell the difference between the VRO fuel pump that mixes the oil/gas and the VRO pump that does pre-mix only, by the number of hose inlets.
By the way, it's not very hard at all to do a fuel pump demand test on the lake. Just takes time to plumb in a T fitting between the fuel pump and the Vapor separating tank.
Extra fuel hose that is the size needed for the link between the fuel pump and VST.
Insert an appropriate T fitting of the same fuel hose diameter size.
Run a fuel line from that T fitting to the front of the outboard, then cap it off and clamp it down until you're ready to test the fuel pressure. Zip tie where appropriate to keep the hose manageable.
Buy a step down adapter that will join your T'd temporary hose at the front of the outboard to a vacuum/fuel gauge hose.
Use appropriate clamps to secure the fittings from leaks.
Now you got access to doing a fuel pressure test with the engine cowl off on the water, at load at speed. You'll just need a helper driving the boat while you monitor the fuel pressure gauge.
That may be overkill for your current circumstance if the service manual requires the following and your fuel pump/lines pass this:
1. You should have X inches Hg. of vacuum or less on the intake side of the fuel line/pump with no bubbles.
2. You have a stable X PSI at specified RPM level in gear, usually I believe that is about idle for most motors.
However, if you experience any symptoms of leaning out only when getting close to WOT RPMs, expect that a fuel pressure test on the water at speed may be the only route.
