Johnson venom 225 issues

[Jakester136]

Ok guys, I could use some help figuring out some issues. Motor is a 1997 Johnson Venom 225 I’m trying to line out this motor. this motor had a new power head along with carb rebuilds and a variety of other work in late 2018 and has done a lot of sitting since then. model# J225STLEUD.

what it’s doing.
it idles fantastic on the hose and in the water, off the trailer it took off, ran strong, will rev 6k rpm. If I come to a stop shut down and go fishing for a while it will fire right up with a bump of the key, but when I go to give it throttle it will bogg and die, if I leave idle for several minutes, warm it back up and keep feathering the throttle it will snap out of it and take off like a rocket. Every time I shut down the problem returns. I also think my primer solenoid is bad, I can hear it click when choke is engaged but is very hard to cold start unless I open The red bypass valve, prime the bulb, then it will fire right off. I’m also getting a lot of fuel/oil on the plugs

what I’ve done
pulled all the plastic carbs apart and deep cleaned, checked float levels ect. All new fuel lines from the tank, pump, carbs. Left throttle bodies in tact. haven’t touched the needle’s or taken the side plates off the throttle bodies yet. Idle timing on water is 4 degrees ATDC. I’ve played with the timing some to see if it changes, no change. compression test. 108-110 psi on all cylinders

neutral idle on the water is about 1200 rpm and 750 in gear.

used in-line spark tester, have spark on all 6 banks at idle.

my VRO is bypassed, I’m mixed 50:1 with Lucas oil and a couple cans of sea foam.

need some ideas where to go from here. Thanks!

[sharpeye Mike]

I'm thinking that your priming bulb on the hose is giving you the problem. Your gas is going back down to the hose.

[Muskoka2]

I'm thinking that your priming bulb on the hose is giving you the problem. Your gas is going back down to the hose.

I've got a '00 225 H.O. & sometimes in hot/humid weather it'll bog on takeoff when skiing etc. It passes quite quickly-vapour lock?

[Jakester136]

I'm thinking that your priming bulb on the hose is giving you the problem. Your gas is going back down to the hose.

I thought the same thing, Replaced with new one, did same thing

[Jakester136]

I've got a '00 225 H.O. & sometimes in hot/humid weather it'll bog on takeoff when skiing etc. It passes quite quickly-vapour lock?

this one takes several minutes to get it to plane out again.

[flabum1017]

Make sure whatever you used to cap off the oil inlet on the VRO hasn't cracked and letting air in.

Change that Primer, it could be partially stuck open. You can test this by taking the small lines off and pumping up the primer bulb hard and see if any fuel drips out. Could be flooding it while sitting.

Also, be sure the red lever is in the correct position:

[Jakester136]

Make sure whatever you used to cap off the oil inlet on the VRO hasn't cracked and letting air in.

Change that Primer, it could be partially stuck open. You can test this by taking the small lines off and pumping up the primer bulb hard and see if any fuel drips out. Could be flooding it while sitting.

Also, be sure the red lever is in the correct position:

thanks for the tip on testing the primer solenoid, I will do that. Also I guess I’m a little confused on what you mean by capping off the oil side of the VRO, the way this pump is set up (was done before I got it) there is just a fuel line in to the bottom of the outside section of the pump, and then a line out of the top of the pump that goes to the fuel rail, and then the line on the inside bottom of the pump to the crank case

[flabum1017]

thanks for the tip on testing the primer solenoid, I will do that. Also I guess I’m a little confused on what you mean by capping off the oil side of the VRO, the way this pump is set up (was done before I got it) there is just a fuel line in to the bottom of the outside section of the pump, and then a line out of the top of the pump that goes to the fuel rail, and then the line on the inside bottom of the pump to the crank case

There are two pumps that look similar.... One is VRO pump, it will have a 3/8" suction for the fuel, a 5/16" suction for the oil, a 3/8" outlet and a pulse nipple to run it. Then there is a fuel pump that has the same housing but without the oil section. If you have the VRO pump, the 5/16" oil suction nipple needs to be plugged off or it will introduce air bubbles into the fuel.

[flabum1017]

Wrong thread

[Jakester136]

There are two pumps that look similar.... One is VRO pump, it will have a 3/8" suction for the fuel, a 5/16" suction for the oil, a 3/8" outlet and a pulse nipple to run it. Then there is a fuel pump that has the same housing but without the oil section. If you have the VRO pump, the 5/16" oil suction nipple needs to be plugged off or it will introduce air bubbles into the fuel.

ill look again tomorrow, I’m almost positive there are no un-used or capped ports on this pump

[Jakester136]

If it's still apart, check the reeds too.

looks like this

[flabum1017]

looks like this

That's the fuel pump only version, you're good.......

[flabum1017]

looks like this

Your fuel primer is disconnected.................

[Jakester136]

Your fuel primer is disconnected.................

yessir that’s because I just had it apart to test proper function of the plunger and valve. It is working proper. Just had it at the lake again today,
same issue. Runs amazing, not fouling plugs, no misfire, no sneeze, set timing @ 4degree’s at idle in gear and 16-17 degree’s max advance at 4500 rpm. Not losing fuel prime, I have a clear filter and it stays full. I can Run and idle as long as I want with zero issue. Soon as I shut and let it sit any amount of time it will fire right up and idle perfect. Soon as I go to give it throttle it will fall on its face and die if I give It too much throttle. After I sit there idle for several minutes and feather throttle it will hesitate and then snap out of it and run perfect again until I turn it off and let it sit. I forgot my Alan wrench so I couldnt Adjust the needle valves on the water. Once I got It home I back Them all out one full turn and will test it again tomorrow to see if that makes any difference. Honestly I’m confused as hell right now. I even drained all 6 carb bowls when i got back from the lake to make sure the carbs aren’t draining out. They were all full with fuel

[Jakester136]

Thanks for all your help thus far by the way.