Strange Bogging / Hesitation Issue with Evinrude 150XP V6 Outboard

[1983 ercoa 21']

As to the rev Limiter they could have changed pp to ones that's not limited.
as to the choke to clear it up that is a lean sign. If IT was a sticking timing base it would make it worse by booging it down.

 

[wespants]

So in other words if the timing were more advanced it would be even more lean? How do I adjust the mixture? When I rebuilt the carburetors I didn't notice any adjustments to speak of.

 

[1983 ercoa 21']

The only way to do so is jet change. But id be looking at something with the fuel system. I don't remember if you changed all your fuel lines or not? I'd also be checking fuel pump pressure. I don't know how to express how important a good fuel system is to a two stroke motor because it also supplies the oil. When going through my new to me motor after it sit for several years I didn't hesitate one sec cleaning,inspecting and replaced all hoses including primer hoses and bypass hoses . . Have you ever had someone pump the bulb when your having this issue to see what happens? If pumping bulb corrects issue it's a supply issue. If supplying extra fuel via the choke /primer corrects the issue says it's a dirty carb issue plugged jet . It's very doubtful that you need to rejet the carbs unless this motor came from a high altitude area where it would have been leaned down from factory setting.

 

[wespants]

Great information, thank you! I've had the fuel lines replaced from the tank to the pump. Nothing past the pump. Was considering doing it. When it has done it in the past, I tried pumping the bulb to know avail. But, that was before the fuel lines were replaced. I'll try that again. I suppose I could've sucked something else into a jet. So when I go to swap my plugs maybe this coming weekend, I can look at the plugs and see if any of them look like they've been running lean. I do need to run it a few minutes first before checking that though, right?

 

[1983 ercoa 21']

Personally I find two stroke plugs to be harder to read because your always burning oil with the gas therefore they always seem to read a little darker to me.
everything I read says to have the motor on lake at wot kill ignition and put into neutral and when you come to a stop pull plug.
are you removing all the jets and cleaning all the passages?
I'm really thinking you have one or more hoses breaking down after the filter. You should replace any and all old hoses to insure a good system. I also believe you are and have been chasing more than one bug like I did. I think you have found one with the sticky timer base now squash the one in the fuel system. If you go to a parts store rather than a marine supply to get hose get the better fuel injection hose rather than the cheap fuel line that will fall apart in a year or less. You should also run another compression test after warming up the motor on the muffs

 

[wespants]

This all sounds very solid, thanks! I will look and see what size my hoses are then order some marine grade fuel line and replace it all. There is a plastic header pipe that splits three ways to feed the carburetors. It is hard plastic. I guess I can leave this alone as long as it seems in good condition?

I did not remove the jets when cleaning the carbs. I saw them there, but didn't see much point in unscrewing them since I was dipping the whole thing anyway. Did I make a mistake here? I dipped them in ChemDip for about 30 minutes then blew the passages and jets out with compressed air, making sure that air was exiting from the opposite sides.

I guess I will do the fuel lines and new plugs first, and see if I still have the problem and if so open back up the carbs. And after I do my decarb, I will do a compression test the engine warm. I was actually thinking about stacking these events together for efficiency. Use the decarb activity to warm the engine, pull the plugs to do the compression test, then install new plugs.

 

[1983 ercoa 21']

Yes the fuel manifold should be fine. Go back and disassemble the carbs one at a time as to have a reference if needed. You will need a long shanked #1 flat head screwdriver to remove the jets in the bowl make sure you get all of them. Look at your book or pull it up on line. Ps Chem dip mainly removes fuel varnish not rubber .

 

[1983 ercoa 21']

I'm sure there is cheap marine grade fuel line out there this is something that should be a hands on purchase. Take the fuel line and make a tight loop making sure it doesn't kink on you reason being is there are elbows that are formed for tight places that are no longer available or pricy there for you can make a loop to get what you need.

 

[1983 ercoa 21']

I'm sure there is cheap marine grade fuel line out there this is something that should be a hands on purchase. Take the fuel line and make a tight loop making sure it doesn't kink on you reason being is there are elbows that are formed for tight places that are no longer available or pricy there for you can make a loop to get what you need.

always use a good carb cleaner like b-12 chemtool and keep it away from the floats,needle,gaskets it can and will ruin them.

 

[wespants]

I'll see if I can find some line local. I replaced the floats, gaskets, etc and didn't dip anything it could destroy. Hopefull those are ok.

 

[1983 ercoa 21']

Any luck finding fuel line?

 

[wespants]

No Title

I was just logging in to give an update and saw you wrote today. I finally just today went by the boat (at storage) to see what size and how much I needed. Been too busy to mess with it. Seems like most of it is the same as what comes from the tank (3/8"?). What was leaving the manifold to the individual carbs appeared a bit smaller. I'll try to go in the next day or two and do some shopping.

Saw a couple of things I didn't understand. On the port side, between the filter and the fuel pump, there was a T intersection. Coming out of this T intersection was a slightly smaller line that went up to something on the port side of the motor. It didn't look like that thing used the fuel, so I'm thinking maybe it is a fuel pressure sensor to trigger the starvation alarm. Should I replace the line between the T and this device? Here's a picture:

 

[wespants]

No Title

Also, I found a fourth line splitting from the fuel manifold feeding the carburetors. 3 feed the carburetors, and this fourth one runs all the way to the starbord side of the motor into this device. I'm guessing this has something to do with the choke. Should I replace this line? Here's a picture (it is the thing with the red lever):

 

[1983 ercoa 21']

Yes 1st picture is for fuel alarm I disconnected mine. The 2nd picture is the primer which is what's activated when you push in on the key this system is in place of choke butterflies. That fuel line needs replaced also along with the line on the little bypass values. The clear weedeter fuel line works for bypass and primer system

 

[wespants]

Ok, cool. Thanks! So those little lines that run to the carbs (not the main fuel lines) are choke bypass? I was thinking they were vacuum lines. Shows what I know. I'll pick up some clear tubing for those too.

 

[1983 ercoa 21']

The ones going to the carbs are primer lines that put fuel in the motor when activated by pushing in on key.

 

[ondarvr]

Just looked at this thread.

The actual compression numbers don't mean much, gauges rarely read the same, the results can be all over the board, it's more important that all cylinders are close. After a decarb it could raise the numbers, that would be good, but it may do nothing.

You mentioned it would surge, what type of surging? If the RPM's change slowly it normally points to a fuel delivary issue, if they change instantly, like a switch was flipped it's normally electrical, this isn't always true, but is most of the time.

All jets need to be removed and cleaned, the fuel pump needs to be rebuilt also.

If you continue to run it with this issue you risk destroying the motor, running lean is very bad for it. (if fuel delivary is the problem)

Answer to an earlier question. The dino just loads the motor to hopefully observe the failure while it's happening real time, with tools and equipment at hand to identify the problem. But if the total output is low, you know there are issues and better performance is available. It can appear to run well even if the timing doesn't reach full advance, just an example.

 

[wespants]

Thanks to you both for the info. It has the original VRO pump but it's had some wires unhooked and maybe some other stuff bypassed I suppose (I premix). If I decide to rebuild/replace, what is the better choice? Replace w non-VRO?

 

[wespants]

Well, I got the fuel lines on the motor swapped out today. I did everything except for the little ones feeding the choke jets on the carbs. They ended up not having the correct size at the part store, and it all seemed to be in pretty good shape anyway. Actually, all of the line was in great shape. I didn't see any evidence of it breaking down or collapsing, but it's done. Unfortunately I'm out of time for the weekend. Have other work to do tonight, and tomorrow after church we will be taking our other boat out for some family time.

Oh, while I was in there I sprayed some carb cleaner (with the straw) through the jets as best I could on all of the carbs. Also, I separated the timing lever from the lever that pushes it and found that the spring is still strong that pushes it, but the timing lever is really gummy. I wore it out good with PB Blaster and it's a little better, but I think the flywheel is going to have to come off. Maybe one evening this week?

 

[1983 ercoa 21']

Not sure how to stress the importance of pulling carbs off and removing the jets and checking all passages. You know you have a fuel problem because choking it clears it up.