1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connections

[tmljunkmail]

I have read a ton of things on this site and I am slowly checking into the possible solutions.

However, before I go and get all crazy, I have a dumb question cuz something doesn't look right to me.

I'll try to attach a pic to help....but if it doesnt work here goes.

I have two fuel hoses....one light grey that goes to the outboard and one black that comes from the fuel tank.

When I look at my fuel/water separator it has four connections (two on each side) like most all of them do. On each side there is what I percieve to be the inlet (marked with an <--- arrow pointing into the unit) and and what I percieve to be the outlet (marked with an ---> arrow pointing out of the unit).

Current configuration has both connections made on the same side. The grey (engine side) line connected to the inlet connection and the black (fuel tank side) connect to the outlet.

Isn't this backwards? Shouldn't the black (fuel) line be connected to the in arrow and the grey (engine) line be connected to the out arrow?

Could this be part of my problem?

Any ideas?

 

[achris]

Re: 1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connectio

I...Current configuration has both connections made on the same side. The grey (engine side) line connected to the inlet connection and the black (fuel tank side) connect to the outlet.

Isn't this backwards?

Yes...

Shouldn't the black (fuel) line be connected to the in arrow and the grey (engine) line be connected to the out arrow?

Yes...

Could this be part of my problem?

Any ideas?

You got it....

Easiest fix I've had for a while. A 'self-fixing' post. ... Swap the hoses...

Chris.......

 

[tmljunkmail]

Re: 1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connectio

Thank goodness....I thought I was going crazy.

I assume it doesn't matter if they are connected on both sides of the separator so long as out to engine is on an "out" arrow and in from tank is on an "in" arrow? Correct?

Do we think this will help with the surging?

Its also a total pig out of the hole on start.....I don't suppose I will be lucky enough that this will help that problem too?

Thanks Chris for the quick feedback.

 

[achris]

Re: 1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connectio

Thank goodness....I thought I was going crazy.

We are all a little bit crazy.

I assume it doesn't matter if they are connected on both sides of the separator so long as out to engine is on an "out" arrow and in from tank is on an "in" arrow? Correct?

Correct. Just be sure that the fuel primer bulb is between the filter and the engine, NOT the tank and the filter.

Do we think this will help with the surging?

Possibly... Check spark plugs too and use NGK, not chumpions!!! ('Check' means remove, look at, throw in the bin, put new ones in. ) Not sure if these engines have a rev limiter, but if you're pulling too many revs at WOT, then a rev limiter would give you a feeling of surging... What rev are you making at WOT? Should be 5000-5500rpm.

Its also a total pig out of the hole on start.....I don't suppose I will be lucky enough that this will help that problem too?

Don't know... What about going one size DOWN in the prop.

Thanks Chris for the quick feedback.

A pleasure to be of service, sir....

Chris......

 

[jerryjerry05]

Re: 1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connectio

If you had the leads in and out switched then you will need to replace the filter when you switch them back.It will flush all the gookies into the fuel system.J

 

[tmljunkmail]

Re: 1999 Merc 90hp ELPTO Surging at WOT need help confirming fuel separator connectio

ok.......so I was wrong.....I retraced the lines and the fuel/water filter was in fact set up correctly.

Which means I still have a problem.

I bought a new fuel filter.....new fuel/water filter.......replaced the fuel line and primer bulb up to the engine (from the fuel/water filter)....new plugs.....and did a seafoam decarb on the engine.

Problem is far better.....but still getting some surging (about a 500 rpm jump usually from 3000 to 3500).

I'm going to try the "testing your boats fuel system" post on the FAQ tomorrow.

Anyone got any ideas knowing what I've done before I go through all the trouble?