Narrowing down the issue

[FowlMinded]

Hey all, im new here but recently bought a 2005 Lowe Roughneck 1860 with a 2005 90 HP Johnson 2 stroke. Been having to do lots of little maintenance to get it back up to par.

Since ive bought it there has been an ongoing issue with the motor losing fuel pressure and dying out, I can prime the bulb back and shoot fuel to the engine but once its primed back it pulls that fuel through and I can watch the inline fuel filter run near about dry. I reached out to the previous owner and asked him about it and he said that it was doing the same thing to him so he put a new fuel pump on it and had only run it twice before selling it. So I ruled out fuel pump and worked my way back. Replaced the fuel line from the engine back to the factory hub where it splits and goes to the tank, bulb, and inline fuel filter, rebuilt the fuel primer solenoid, and im still getting the engine dying out. I don't think its the vent hose because I don't have any issues filling the tank up. What am I missing

 

[Captain Caveman]

If the previous owner didn't tell you about the fuel pump prior to the sale, there is an honesty issue. I wouldn't take it at face value that he actually replaced the pump or that he did it correctly. Anybody with integrity would have done a fix and made sure that it worked. He didn't do that so I wouldn't trust him. Check the pump.

 

[ahicks]

A bad pump isn't going to empty an inline filter (assuming the filter is between the pump and the tank?). Not in my mind anyway. It sounds to me like something is sucking air between that filter and the pick up in the fuel tank. Is there any dampness or fuel stains anywhere along the fuel route in that area that might help diagnose?

 

[gm280]

If the fuel filter is running dry, maybe your tank isn't vented properly. Air has to replace the fuel being sucked out of the fuel tank. And if the vent isn't open enough that would cause that issue. JMHO

 

[FowlMinded]

I thought the same thing as far as the fuel pump. It’s pulling what fuel is there but nothing was replacing it. I tore into the boat and blew out the vent tube in the gas cap after removing it from the tank. Nothing came out of there, so then inspected my fuel lines from the tank and they were super old probably OE from the factory in 05, they had a small split in them not quite all the way through for fuel to be pumping out but I believe enough for air to enter under the vacuum. Replaced those with some new armor flex fuel lines, ran it all the way to the motor. So fingers crossed tomorrow that solves the issue

 

[FowlMinded]

Still no good. So far I have pulled the tank, checked the vent hose, blew it out, checked the pick up tube cleaned it, ran brand new line from the tank to the motor, replaced the bulb (Attwood bulb, have an OEM on the way) replaced the in line paper filter, cleaned the filter on the motor itself. Looked closer, fuel is coming into the filter, not rapidly but it is trickling in. Not enough to replace the fuel the motor is burning. It will idle all day long but as soon as I give it throttle it will run and then die back and as soon as I back off the throttle it cuts off

 

[ahicks]

If there's a restriction on the output side of the pump, the pump can suck it's brains out, but if there is no place for the output to go (air or fuel) that filter is never going to fill!

Might be worth the trouble to check the line from the pump to the carb - or better yet, just replace it. Still leaves the potential for a gob of something to be plugging the carb inlet....

 

[gm280]

When was the last time you inspected the carb(s)? Could be time to address them and make certain all the fuel passages are open and clean. When dealing with fuel openings, it is amazing how little bit of build up can change the flow. Math proves that out when you do the pie X radius squared formulas. So any build up anywhere in the series of things will keep the proper flow from happening. Just because you can idle the engine without issues, doesn't mean the carb(s) are being supplied enough to keep up or the carb(s) themselves are clean and all passages open. JMHO

 

[froggy1150]

Here is a test you can try.
#1 FIRE EXTINGUISHER
#2 remove fuel line at carb and route to a can
#3 i use a metal oil can with the squeeze hande filled with gas when i prime motors to start. Use something like that to start and run motor
while running look to see the flow of gas going to can. If flow is good check carb. If not work backwards

BE SAFE

 

[scoutabout]

Ya, based on all that good work you did on your tank and lines I'd be eyeballing that supposedly new pump, then look for anyplace with potential for air leaks, then carbs. Good luck let us know how you get on.

 

[racerone]

I recall the motors from the 1960's 40 HP and such.------Ran with the wee filter / sediment bowl always looking empty.

 

[FowlMinded]

Update:

rebuilt the fuel side of the deleted VRO pump. Diaphragm around the ring was absolutely shredded. Now I keep plenty of fuel pressure but decided to break down the carbs to make sure no rubber passed through into the bowls.

broke them all down completely replaced a few gaskets, sprayed carb cleaner all over them, then blew out with the air hose.

put it all back together and I have the same issue as I started with at the beginning. I can crank it and it will idle, albeit roughly) but will eventually cut off. I’m thinking now it could be flooding. The bottom left carb, is pouring out fuel while all the other 3 are dry. Pulled the bottom off again adjusted the float (or so I thought) put it back on and it’s still dumping fuel in the carb. None of the others have any gas at all coming out of them. They are pretty dry. Pulled the plugs and checked them the bottom left was covered in oil and gas. It has spark and compression in the cylinder. What’s the proper way to adjust these carbs, I have the high jet seated all the way in the bowl, the idle screw I backed it in tight and pulled it out 4 turns on each.

Im lost, I have no other ideas

 

[Kingmt01]

Did you adjust all the carbs or just the one?

 

[FowlMinded]

I took them all off and cleaned them. Took that last one off again and cleaned and polished the seat and needle. Made sure it was adjusted right. Hooked it all back up and about to run it again on the hose. Reset all the idle screws (the one with the spring I’m assuming) all to 2.5 turns outside of the seat. Going to see how it runs now

 

[FowlMinded]

Adjusted the float, no longer flooding. I can crank it and it will idle, it will idle high then back down idle high then back down then eventually die out. If I Rev up the engine it runs and then it dies right out. I’m at a loss, replaced everything from the tank back to the engine.

only thing I can find is when I spray carb cleaner around all the fuel components, right around where the 90 degree nipple goes into the engine under the water separator, when I hit that the engine bogs down, so I’m assuming there’s a vacuum leak right there.

took the fuel pump back off inspected the o ring on the nipple into the fuel pump. It looked good, inspected the O ring going into the engine, it looked good but did seem like it was a litttllee loose in the hole that where it inserts.

would a small leak like that cause all these issues I’ve been dealing with

 

[Kingmt01]

Definitely

 

[FowlMinded]

Replaced the o rings going from the outlet on the pump. Ran a little bit better but still died out after 2-3 minutes idling. Waiting on the anti siphon valve and full pick up elbow, old one was seized up and snapped

 

[Kingmt01]

I can't remember how you said you adjusted the jets. I usually start at 1¼ turns out. How are you syncing multiple carbs?

 

[FowlMinded]

i think spec on these were 5-3/4 turns out from the seat, then adjust down or up. That's about where I started out, going to check compression this afternoon and see where that rabbit hole leads.

as far as syncing goes there are no external adjusts you can make to my knowledge. There is a shaft that runs through the middle of the 2 carbs on each side that tie them together. Only thing I can see is the cam roller is not hitting the cam when the butterfly is closed completely. It lacks about 1/4" from hitting. So theres some dead space inbetween when the throttle moves up til when it actually hits the cam roller

im also wondering can the motor not be charging the battery up enough to keep it running and it die off electrically?

 

[Kingmt01]

"not be charging the battery up enough to keep it running"

It's possible but wouldn't be my first thought. A battery charger hooked to it should keep that from happening tho.

"It lacks about 1/4" from hitting"

But is it opening them at the exact same time & amount?

You can fine tune sync with the idle jets. You'd have to have a vacuum port to read it tho. I'm trying to comment on a engine I don't know anything about so picturing it is hard.