1999 Johnson 115 Vapor Separator Gasket Leaking, Won't Start

[Captain Jeff]

The boat didn't get used last season so it hasn't been run in well over a year. I tried to start it today. First off, the fuel system completely lost its prime while in storage. I disconnected the fuel line from the engine to the bulb and the fuel that poured out was blue with quite a bit of oil in it. It had worked its way into the bulb too as it came out as I primed it. Any reason why oil backfed through the fuel line? (I am still using the VRO)

I noticed the gasket to the vapor separator top was leaking when I squeeze the bulb. Is that the likely reason I couldn't get it started? I am getting good spark.

Obviously the vapor separator cover gasket needs to be replaced. I am planning on replacing the float, needle, and seat while I am at it. Is there anything else I should replace while I am in there? Thank you

 

[Chris1956]

A leaky vapor separator cover should not cause a no-start condition. You might see if you are getting fuel thru the VRO (actually called OMS) pump, to the carbs. Also see if the primer is functioning, as it will be real hard to start if the primer is kaput. Inject some premixed fuel into the carbs to help her start.

I think it is a good idea to rebuild the vapor separator.

 

[Captain Jeff]

A leaky vapor separator cover should not cause a no-start condition. You might see if you are getting fuel thru the VRO (actually called OMS) pump, to the carbs. Also see if the primer is functioning, as it will be real hard to start if the primer is kaput. Inject some premixed fuel into the carbs to help her start.

I think it is a good idea to rebuild the vapor separator.

Thank you Chris, I will try that out and definitely rebuild the vapor separator. What about replacing the diaphragm on the vapor pump? Also you think it is worth rebuilding the carbs while I am at it? It has been at least 5 years since they were rebuilt. Thanks

 

[jakedaawg]

If you clean the carbs you should do the throttle bodies as well. Those passages cause more issues in my opinion, and are easier to get dirty.

 

[Captain Jeff]

Thanks jakedaawg. That is the idle needle and the little door on the side held in with one screw correct? I think the carb kit comes with a new gasket for the side access door.

 

[jakedaawg]

Thanks jakedaawg. That is the idle needle and the little door on the side held in with one screw correct? I think the carb kit comes with a new gasket for the side access door.

Nope, depending on year and model number the throttle bodies are the shiny things that your carbs mount to.

 

[Chris1956]

Jeff, If that motor is a 60* V4 model, the carbs are plastic and contain a float and inlet needle, a high speed jet, and some gaskets. The throttle bodies contain the throttle plate, idle needle and circuit, and midrange fuel circuit, Both the carb and throttle bodies have side covers.

When I clean the carbs I remove them, clean and rebuild with new gaskets and inlet needles. I try to remove the covers on the throttle bodies, so I can use some gumout jet spray to clean the idle needles, without removing them.

5 years between carb cleaning is not a lot. If you use clean, fresh fuel, the carbs stay pretty clean. Check the carb bowls for warping. It probably makes sense to rebuild the vapor pump as well.

 

[Captain Jeff]

No Title

Hey everyone. I took apart my vapor separator and pump. I bought a new diaphragm for the pump. When I opened it up, there is a aluminum coin type piece inside that is all chewed up (see picture). Can I run it like this or can I get a replacement coin piece? I don't see it in the parts diagram.

Also, the needle and seat kit for the VST comes with a little red washer for the seat. My old seat didn't seem to have one. Is it ok to use that washer? Thanks!