90 TLAT Johnson Engine Problem

[smokeeater163]

Alright fellas,

The dilemma I have I believe is fuel related, but I'm no outboard mechanic. First off it's a 1993 Johnson 90 hp. It will start and idle for a few minutes. However, it will begin to run rough and die unless you pump the primer bulb again. Last time on the water I could get it to idle, but when in gear and trying to take off it would fall on its face and die. I never got it to stay running while in gear. I had the carbs rebuilt 2 years ago and replaced the primer bulb and fuel line to the engine, but not the fuel line from the bulb to the engine. Today, I pulled the entire fuel line off and put new line on and used the same bulb and my problem still continues.......

Could this be the fuel pump? Carbs?

Let me know your thoughts please

[ChampioNman]

Could be.

[Bassmeister]

I'm thinking fuel pump....

[smokeeater163]

Is there a rebuild kit for it or a cheaper place to find a new pump? Maybe a part number if you have one available?

[smokeeater163]

Or maybe a way to eliminate the VRO pump and install a electric fuel pump?

[ChampioNman]

https://maxrules.com/fixomc-no-oil-vro.php

Part MTM-03-70 premix fuel pump for 90* cross flow motors.

[smokeeater163]

Awesome..thank you! Screenshot_20190825-125414_Amazon Shopping.jpg

[smokeeater163]

Is this the same pump? Looks like it just doesn't come with zip ties and fuel line.

[ChampioNman]

I don't see the isolating washer either. The zip ties are special #0320107 BRP uses a curved end so there are no gaps to allow air in. Good luck with your purchase.

[omcforever]

Or maybe a way to eliminate the VRO pump and install a electric fuel pump?

Bad idea. Safety issue.

[smokeeater163]

What's a bad idea? Buying the pump Championman is talking about or something else?

[Buccaneer]

The electric fuel pump is a bad idea.

[smokeeater163]

One last question...is there a way to test the pump before I just replace it?

[ChampioNman]

there is a way to test to see if the diaphragm is OK, you'll need an air pump with gauge, such as a basketball pump attached to the fuel inlet side of the pump and you'll need to cap off the outlet pump the up the pressure to 5 psi and will need to hold for 15 minutes.

[smokeeater163]

Screenshot_20190904-203633_Gallery.jpg ok, so I have the pump coming, but not sure about actual installation. My VRO pump.has 4 lines connected to it, but the new pump only has 3. Any insight would be appreciated on that. Also, Do I have the arrow pointed at the right spot where the new pump needs to mount to?

[ChampioNman]

Well you are going to be premixing so there goes one hose. So you'll have fuel in that will go to the plastic housing labeled filter. Then fuel out, and your pulse line from the crank case. Should mount to the side of the block. I believe the screws are 10-24.

[smokeeater163]

20190907_182727.jpg thanks for all the input along the way. Here is the new pump mounted and ready to go. Unfortunately, my battery is completely shot and cant take it to the lake to see if it works. I'll let you know if not though...lol Thanks again Championman!