Starting outboard with high pressure in gas tank?

[kipper12]

I happened on this by accident. Usually my 97 evinrude 8 hp 2 stroke takes 5-10 pulls to get going when cold. Yesterday I primed the tank and forget to open the valve. It was left that way about five min while I put it in the water. I pulled the choke and it started first pull. The only reason I noticed the valve wasn't open was I went wot and it died. My question is should I do this as standard practice on startup to make it easier to start then open the valve or could this cause damage?

 

[JB]

Re: Starting outboard with high pressure in gas tank?

What valve are you referring to, kipper? The vent in the tank cap? Leaving that closed will cause the engine to die from lack of fuel pretty quickly, but priming primes the carb, not the tank.

I would first make sure that your experience is repeatable, not simply coincidence.

Let us know.

 

[HighTrim]

Re: Starting outboard with high pressure in gas tank?

I agree with JBs thoughts here, if you are referring to the tank vent, having it opened or closed has nothing to do with startup.It will kill your motor while underway though as you found out as it creates a vaccuum. Likely just a coincidence. Did you do anything else different on startup? Certain motors seem to like their own startup procedure, once you find one that works for you stick with it.

Perhaps your choke was not functioning properly before? That motor should definatley not take 10 pulls to start. Are the plugs wet after the first few pulls? Will putting a bit of premixed fuel directly into the cylinder cause it to start instantly?

 

[kjdunne]

Re: Starting outboard with high pressure in gas tank?

Almost hate to ask, but by "prime the tank", I assume you mean pumping the bulb in the fuel line. Is the arrow on the bulb pointing toward the engine? Does it get firm / hard?

 

[kipper12]

Re: Starting outboard with high pressure in gas tank?

Thanks for the replies guys.

Sorry for the incorrect lingo. It's my first boat. I know car engines fairly well just not the particulars of the marine variety or much 2 stroke.

To answer your replies,

Yes it's the vent in the tank cap.
Yes I mean pump the bulb.
I have repeated this again and it seems to prove true. Could be one of two things. Either extra pressure in the line from having the valve closed and or simply pumping the bulb and letting it sit for five minutes after that before trying to start.

I guess I'm wondering if this is normal and if not should I be able to pump the bulb with the vent open and have it start first pull?

 

[64osby]

Re: Starting outboard with high pressure in gas tank?

The bulb should have a one way valve in it. This is what allows it to feed fuel to the motor.

If the valve in the tank is closed, priming the motor would cause the tank to have a small vacuum, not extra pressure in the tank.

The five minute wait with a primed system should ensure there is ample fuel for start up.

You should be able to prime the bulb with the vent open and have the motor start. Maybe not the first pull but within 5 pulls if all systems are operating properly.

 

[kipper12]

Re: Starting outboard with high pressure in gas tank?

The bulb should have a one way valve in it. This is what allows it to feed fuel to the motor.

If the valve in the tank is closed, priming the motor would cause the tank to have a small vacuum, not extra pressure in the tank.

The five minute wait with a primed system should ensure there is ample fuel for start up.

You should be able to prime the bulb with the vent open and have the motor start. Maybe not the first pull but within 5 pulls if all systems are operating properly.

Cool well that answers my question. I guess priming the bulb 5 min before start is what makes the difference. :joyous:

 

[HighTrim]

Re: Starting outboard with high pressure in gas tank?

Cool well that answers my question. I guess priming the bulb 5 min before start is what makes the difference. :joyous:

I honestly cannot see what difference that would make. You are just simply filling the carb bowl.

 

[64osby]

Re: Starting outboard with high pressure in gas tank?

You should be able to prime the bulb with the vent open and have the motor start. Maybe not the first pull but within 5 pulls if all systems are operating properly.

I honestly cannot see what difference that would make. You are just simply filling the carb bowl.

HT - That's why I added my last line.

 

[kipper12]

Re: Starting outboard with high pressure in gas tank?

I have no idea. My original thought was that the priming bulb pressurized the tank thereby pushing fuel into the engine. Going through this thread I've learned it just pumps fuel into the carb...

What I do know is that it's worked multiple times now. I connect the fuel line, pump and leave it for a few min then try to start. First pull three times now. 5 pulls last time I tried do it right away.

Is it possible there is some kind of minor clog in the carb and that letting it sit allows fuel to seep in further..... I dunno maybe grasping at straws.

Either way I'm pretty happy with it. I only paid $350.00 and so far it runs fine. I'm going to run some seafoam in the next tank just because and change the lower gear oil sometime in the next week or two. I'm sure I'll have questions then.

I appreciate all the assistance here!

On another note I also learned its a 96 motor not 97 by the model #. I just took the guys word for it not that it makes much difference until I need parts though.

 

[RogersJetboat454]

Re: Starting outboard with high pressure in gas tank?

I'm going to run some seafoam in the next tank just because and change the lower gear oil sometime in the next week or two. I'm sure I'll have questions then.

While you're servicing the business end, you might as well order up a water pump kit, and replace the impeller. Something that's routine maintenance that should be done every couple years...