1999 Johnson 225 Ocean Pro Fuel Pump Problem or Something Else?

[Bteach]

J225pxeec model. Good Compression on all cylinders, cranks and idles fine. Runs up to about 4k rpms and then dies down. If i let off the throttle and slow down it will build right back up on fuel pressure and allow me to run it at 4k rpms again. Bulb doesnt suck flat but when I pump the bulb I can run the boat at higher than 4k rpms so it seems a fuel issue. All the carbs have been rebuilt and gone through a second time to make sure I didnt miss anything or put back together wrong. VRO Fuel pump that has been switched to pre mix. Pump has been dismantled, cleaned, and put back together and nothing seemed broken or overly worn. First time dealing with a VRO so I could be overlooking something involved with that portion. Tank was drained this summer and fresh fuel and additive has been added. No alarms when running the boat. Tank and filter have been bypassed and run on a 6 gallon and the same issue so it seems fuel pickup from tank is not a problem. Any insight?

 

[jakedaawg]

Are you still using the VRO just with oil disconnected? I haven't seen many conversions that worked...

Has it ever run well for you?

check for air leaks at all fittings and vst cover...

plumb in a clear hose and vacuum guage at cowl connection. You're looking for less than 3.5 in/hg and no air bubbles.

make sure pulse limiter and pulse hose is clean, tight, and not kinked.

 

[racerone]

Perhaps there are issues with crankcase compression that drives the pump.

 

[Bteach]

It never has. I purchased it about a year ago and it had been sitting for a few years. When i got it a mechanic came out and we did compression tests and cranked the engine. There was clearly leak on one of the carbs and the spark plugs needed changing. So it ran rough and I attributed it to those problems and probably buildup in the carbs and possibly water in the gas. Jakedawg...what is the VST cover? I havent dealt with larger motors so im lacking in knowledge. Yes I am using the VRO. It was done when I got the motor and a sleeve was put over the oil end and tightened down. The wiring for the VRO was just disconnected. Am i right in stating the pulse limiter provides air to the pump for compression? I will be sure to check on it as well as try testing pressure with a gauge. Racerone, if anything is wrong with the fuel pump as far as compression, I assume a rebuilding kit would fix that, correct?

 

[racerone]

The pulse limiter protect the pump from high pressure spikes.----It is a " flow fuse " as such.----Crankcase compression drives the pump and that is totally separated from cylinder compression.

 

[Bteach]

I understand Racerone, and obviously no real way of testing the crankcase compression. I was thinking of just buying a new fuel pump rebuild kit and going through it as well, in case something not clearly visible was wrong with it. The carbs were really gummed up when I rebuilt them so I could imagine that gas lines and any filters that I may have overlooked could be the same. With that being said, I just watched a video that showed filters in the male end attachments on outboard fuel pumps. I didnt notice one in mine...did I overlook something?

 

[jakedaawg]

The VST is the grey rectangular shaped tank on the bracket between the carbs. It has a float in it. Open it and inspect for cleanliness and float operation.

 

[jakedaawg]

Being 20 years old I dont think you would waste money by replacing all fuel lines and cleaning fuel rails and replacing the orings and gaskets of the various fuel components. Just start at the cowl connection and work one piece at a time through it all so you do not get lost.

 

[racerone]

Jake----Does this motor have the VST ?

 

[Bteach]

I dont think has one.... Maybe im missing something but the 6 carbs have nothing between them but the gas "tree" that connects the fuel pump to the carbs. I havent paid attention to anything else but the carbs and fuel pump so maybe its in another location and if so I will definitely inspect the condition.

 

[jakedaawg]

My bad, sorry. Sometimes the v-6 configurations get confusing to me...

verifying the fuel lines are good is still something I would do before replacing/rebuilding the pump.

cleaning the pulse limiter (purple or black round thing at block that the pulse line comes from) and inspecting/replacing pulse line would be high on my list also. It doesn't take much of a pinhole kink/twist to effect pump operation.

I am just trying to give insight into things to verify before you condemn based on crankcase pressures...while that happens, I find it to be rare but I live in a area where boats are only used for 12 weeks a year.

 

[jakedaawg]

...double post

 

[Bteach]

I understand. I’ve come home from work and pulled it apart. I pulled the carbs, throttle bodies and the reed block form the lower end of the motor (easiest way to get to the pulse area) and there are two smaller than dime size filters on the face of the cylinder case that seemed dirty. I cleaned them and the back of the reed block that runs to them had a fair amount of trash in one of the ports that was probably blocking the filter some. I’m unsure of its use but I’m gonna assume fuel input. I’ll need a new gasket before I can put it back together but the pulse hose was good as was the port. I’m going to go ahead and order a fuel pump kit just so I know it’s not the issue while I’m at it. Get me a clear hose and a pressure gauge as well and check it all out. Hopefully I will know more by the weekend.

 

[jakedaawg]

Vacuum guage...

 

[Faztbullet]

If it will idle fine and not run out of fuel at idle the crankcase compression is OK and you have a VRO/OMS delivery problem.Most likely the air motor side