1991 Johnson 150 WOT Problem

[flhunter27]

Hello, I'm a new member trying to get some help?
Went out last week and motor ran great all day, fishing a hugh lake and had already shoot across several times. Late in the afternoon motor was idling fine but when i gave her some gas she died. Would Fire right back up but would stall everytime I gave her gas. Trailering was a pain in the behind with this problem but anyhow. Any help would be greatly appreciated.

 

[emdsapmgr]

Re: 1991 Johnson 150 WOT Problem

With the information you provided, it is hard to tell. Could be spark or fuel related. Check each of the plugs to be sure all 6 are firing. A timing light will show if each plug wire flashes. Take each plug out, are they dry or wet? When the engine is running, have someone pump the hose bulb to force fuel into the carbs. (does it run any better). I'd do a compression check to make sure the power head is OK, before putting any big $ into the engine.

 

[rndn]

Re: 1991 Johnson 150 WOT Problem

Welcome to the forum and I agree with the above post.

 

[flhunter27]

Re: 1991 Johnson 150 WOT Problem

Okay,
I took the boat out today to see what would happen. Started fine got out of no wake zone and jump right up on plane. Going WOT for maybe 2 minutes and she starts to sputter. Backed the trottle down and checked the primer bulb. It was soft so I squeeze until hard and she jump right back on plane and ran for maybe 2 minutes again and started to sputter. So it would seem that I have a fuel problem? I did however have a new fuel pump put in maybe 10 months ago. So once again I'm confused and could use some help. Thank You to all who reply.

 

[emdsapmgr]

Re: 1991 Johnson 150 WOT Problem

It does sound like a fuel problem. The engine is consuming more fuel than the fuel system can deliver. At higher speeds, the fuel bowls drain down, and the enigne slows. Running at slower speeds lets the bowls refill again. High speed drains the bowls. Etc. Priming the hose bulb forces fuel into the carb bowls, around the pump and keeps the bowls full. So-somehow you are running out of fuel. The fuel pump is the likely culprit, but if it is new, I'd start looking at the delivery system. On occasion, the primer bulb can cause restrictions in the line. Sometimes the orientation of the bulb (best to have the arrow pointing vertically), sometimes the valves in the bulb go bad. If you have a built-in tank, I'd take the antisiphon valve out and make sure it functions properly. They can collect dirt and it can affect the movement of the ball in it's housing, causing a fuel restriction. Make sure you run a 3/8 hose to the engine. Also possible you have a restriction in the carb fuel inlet, or a float that is either set wrong, or is getting stuck. I also would not rule out water in the fuel. Pump a glass full of fuel out of the tank and let it sit for a hour and see if you have any water at the bottom. Eliminate all the misc issues before you go into the carbs.

 

[flhunter27]

Re: 1991 Johnson 150 WOT Problem

Okay,
I'm trying to figure out what is wrong with my fuel delivery system. First off I have two tanks that connect together at a white plastic thing? That piece apparently has a ball valve that allows you to chose which tank to get the gas. Then from there it goes into some other thing? that looks like an oversized oil filter and then it procedes to the bulb and into the engine. So I wanted to check the antisiphon valve but I'm confused. I took off what I thought was the AS valve but it's hollow with no spring or ball? It came out of a 90 degree elbow out of the top of the port tank. Is the elbow the AS valve? Please help and Thank You.