I have a fuel problem
 

I continue to have a fuel delivery issue

1st I have replaced all the fuel lines, new 10 micron fuel filter, with fuel filter engine side also.

The engine starts fine and in idle runs fine.

When I power up after about 20 secs I loose power and it sounds like the engine does not get enough gas to run at full throttle.

Spend last night trying to trace out what it could be.
I have fresh fuel,the gas lines are not kinked and all are new and I replaced to another new filter yesterday so I want to say that the problem is not there.

My thoughts are that there is something inside the tank that is clogging the pickup

or could it be something engine side

Short of pulling the tank coffin cover to get to the tank which involves removing the center console I need some ideas??????????

If it is a Carb engine the jets may be plugged ?? Happens on my 130 Yammi. Had to replace old hoses because of Ethanol

Jorge, Happy Memorial Day weekend!
You have likely already done this but I would start by connecting a portable fuel tank to your fuel water separator and seeing if that works as normal. Assuming the valves on the fuel/water separator are open, that would eliminate the fuel pump and anything else from the fuel/water separator to the motor.

That leaves:
1). Valve at fuel/water separator is closed (hey, its easy to do, but fortunately as easy to fix)
2). A clog in your fuel pick-up tube or elbow (I've experienced this)
you maybe able to disconnect hose and blow into it. If it bubbles the fuel like a water pipe, the flow is good. However something may be getting sucked into the tube.
3). A broken or separated fuel pick-up tube (Gonna have to go in)...
4). A clog in in your vent (should be able to hear or feel air as you fill tank)
5). You are simply out of gas:o (I've experienced this thinking I had plenty of fuel)

Good luck. Keep us posted.

I think your engine has a diaphragm style fuel pump on it. maybe ethanol ate it up.

I do have a fuel/water separator but it does not have a valve
Clog in the pick up . I blew into the hose and was able to blow back air into tank
broken or separated fuel pick-up tube Could be but the tank is full so I think it may not be that
Clog in the vent ...need to check but I want to say its ok
Out of gas ...its not a 4 stroke but I don't think it used 50 gals yet

Damm I hate this...........

So if it is bad would it run at fast idle but dog it when at full throttle?
It does get up to speed but then after a short time run down to idle but does not turn off

Run it off a 5 gal gas can, that takes the whole (boat side) fuel system out of the equation. If you still have an issue with WOT then its on the motor.
How long has it been since the motor ran? If its more than a few weeks/months with untreated ethanol fuel then its time to tear down carbs/fuel pump. To give you an idea how quick it happens my lawn mowers used to have an issue sitting more than a few weeks (worse over winter) if I didnt treat the fuel!

+1 on the carbs !!! check the bowls !!

How? or is it a wait till I get home thing?

you have to take the carbs off the engine to do this.

I had this same phenomenon. But I could see the squeeze bulb getting sucked flat. If yours isn't, then it is after the squeeze bulb. (Probably the outboard) Mine was a tank that had a straight cut tank pickup just off the bottom of the tank. It wasn't slash cut. It would suck itself flat to the bottom of the tank at full throttle.

My 4 stroke yamaha has inline filters, one per carb float bowl. They are tiny and plug easily- they are the diameter of a 6mm/ 1/4" hose in the float bowl, pinned against the engine block. Those will plug if the rest of the system isn't clean. but a 2 stroke might not have this "feature".

Don't run it long or hard if you think it's running lean, as that's a quick way to overheat pistons, and if you're running premix you're also starving the motor for oil! I'd suggest you duplicate BRP's fuel system test, i.e., in the line between the filter and engine, install a section of clear vinyl tubing with a vacuum gage tee'd into it. When you run the motor, look for bubbles in the clear line from an air leak, and monitor the vacuum gage @ WOT to see how much restriction you have between tank and engine. The limit they use is 5"Hg, but lower is better. Each 90 degree elbow in the system is typically worth about 0.5" Hg pressure loss, but I've also heard of 3/8" elbows that weren't drilled out properly, so they were only 1/4" inside, so that would also cause significant restriction. If you get a high reading indicating a blockage in the pickup tube try blowing back thru the line with a high pressure air hose. Also make sure tank vent isn't plugged up with wasp nests, etc. Maybe try running off a portable tank to confirm problem is in fuel tank.

Sent ya a pm

Isolate and Eliminate - move systematically thru the system 1 item at a time, verify that is working and go to the next item. Doing the extra tank does eliminate the entire tank and filter, then you know further in. The carbs will have a drain screw in the bottom but I doubt that all of them are plugged up but draining will get any crap in the bottom out, squeezing the bulb will flush the whole system - the diaphram fuel pump is a good candidate and a rebuild kit is a minimal cost, check everything along the road, starting at the tank - filter - connector - and just keep going it has to be there someplace

If its a carbed motor with just a diaphram pump it can be bypassed by squeezing the bulb, at least that works on Rudes, although a new diaphram probably wouldn't hurt, should be a DIY job

anti siphon valve might be problem. I have had to remove a couple of them on different boat in order to get adequate fuel flow. You can push the ball and spring out with a screw driver, then test to see if that solves the problem. If not, then I would replace it with another one (not expensive) as they are a nice thing to have (required ;)).

I have had 2 strokes that just pulled gas too fast (drank gas) and would close of the valve. Also, a newer yamaha 4 stroke has a low pressure fuel pump that turns on intermittently at low RPMs (becasue it doesn't pull enough gas at idle), when that pump woudl kick on it woudl lock up the anti siphon valve :mad:

Well I'm home now and I started to go thru it to see what is the problem

Vent line is ok with nothing restricting it
took apart fuel pump and diaphragm looks good
changed the small filter under the cowl
took out the plugs on the carb bowls to see what came out and it looked clean
took some carb cleaner spray and cleaned out the carbs when I took them apart and the insides looked clean, spayed it into every little nook and cranny and into any thing that looked that it could clog and put back together.

replaced all the "zip ties" with SS clamps on the gas lines under the cowl.

The engine fires right up and runs in idle with no problems

I am going to go with an Aux tank to see if it is something in the tank sometime this weekend

All that remains is the pickup in the tank, which involves undoing the console then the tank cover and putting it all back........something that I really do not want to do in the Florida heat and humidity

Jorge we can test it in the canal to see how it runs if you don't want to deal with the ramp and pay the fee.

George, while your at it drain some of the fuel from the fuel line to the motor, maybe a 1/2 gallon or so into a oil pan or some thing like it about 6-8 inches deep and look at it and watch it in direct sunlight. I have seen the separation before and delamination of the fuel lines (black film)in the fuel. I experienced the same identical symtems on my 250 merc a couple years back. It clogged eveything up and I had to rework everything including cleaning the tank.

goodluck bill

Check for screen filter at the top of your pick up tube. Stupid place for a filter but my 1985 had one and so did a friends boat have one. Took me a long time to find it.

Jorge,
If the ball isn't being sucked flat, the problem is in the motor.

I know you've already been in the carbs, but...

I had the identical problem on my Merc Carb 200 and it turned out to be the float valve on one of the carbs. The valve seat had unscrewed a little, so the valve was shutting before the bowl was full. It would run fine at idle, but would starve two cylinders when you opened it up. To check, you should be able to turn the bowl upside down, and the float will be flush with the top of the bowl, assuming yours is the same as the carbs on the 91 through 96 Mercs.

There's another check you can do if you've got the boat in the water. When it starts to bog, hit the enrichener (choke). If it picks up more rpm, the problem is in the middle or bottom carb.

The only other thing I can think of is electrical. Some of the V6 Mercs have a dual stage stator. It uses two sets of coils, one to produce spark below 3000 rpm and the other for over 3000 rpm, if memory serves. This is what I thought was wrong with mine when I figured out it was a fuel issue.

Good luck,
Dave

Blue thanks for the heads up

I think I'm going to take it to Mike let him work on it

Mike Flower? If so he is very good and honest. He fixed my fuel problem.

I was fooling around with the boat and I saw something that may be related to my problem. And if not it will create a problem later

I replaced the spark plugs not to long ago and today I noticed that the top 2 on each side of the engine were rusted and you could tell that salt water was seeping out of both thermostat housings dripping on the 2 plugs. Now when at idle and with the cowl off it does not leak but I imagine under increasing throttle it does leak.

Would this water going all over my spark plugs not effect it?

I took off the thermostat housings and there was no gasket to prevent it from leaking

Either way tomorrow I will replace the 2 thermostats and the 2 housings, they were not in great shape so that will be replaced also

Just wanted to know if this could be the issue or part of the issue

Don't know Mike Flower but I use Mike Fernandez out by Tamiami Airport

If your taking it soundsville he loves those older mercs like that. He says its his specialty.

I bought the 2 new thermostat housings and installed them yesterday.
Found it odd that it shows that there are no gaskets that go in-between the housing's and the head, but placed the thermostat's in position and tightened the bolts and placed the hoses in position with new clamps. Cranked the engine and it still leaked from both sides where the housing meets the head. Tightened them a little bit more but still would leak.


I looked at a parts schematic and it does not show any type of gasket either

My next idea is too either use some type of form a gasket or make a gasket out of material ?

Or is there something I'm not seeing??????

we all do good luck

made a gasket out of form a gasket and no leaks now

Hope that cures it

Now I need to wait till this Wednesday to head down to Islamorada for the 4th

Old school here. Take the air box off and put your hand on each throat while runnin`.
If you hear more rpm in one, there you go. Don`t do this for long, just to see if you can isolate to one throat. As Bushwacker said runnin` premix can be a double edged sword.

Have you done a compression test? That is always tops on my list.

Cheers,
Us.

I had a similar symptom show up on my 4stroke and it ended up being the downstream check ball in the bulb. Mine seemed to work fine and after squeezing it many times, (no comments required ;) ), I happened to feel the ball suck back upstream towards the tank. Replaced the bulb and haven't had any trouble since. good luck!

Well at least I can say that the thermostat housings do not leak any more

The bad is that I still have a fuel problem, I had someone look at it (not a mechanic) and from going through what it could be it looks like it may be the fuel filter diagram.

what else could it be?

If it was a stoppage in the tank the primer bulb would run flat?

the primer bulb is new, the fuel filter is new the fuel filter under the cowl is new, the fuel lines are new, the carbs are clean Have fresh gas

But it being the 4th all is closed down here, but tomorrow is another day.

So it's off to get the parts

Jorge, Happy Independence Day!

Have you tried connecting a portable tank to your motor yet? If not, I urge you to do that next. Isolates the problem to fuel supply or motor. Also make sure that the valves of the fuel/water separator are open and that there is no water or crud interrupting the flow there.

Here's what I found in my supply elbow when I unscrewed it from the tank. Never really sucked the ball flat but would cut out when it reached the anti-siphon valve.

Also, when you went through the carbs, did you make sure none of the floats were sunk thereby flooding a carb?

http://i261.photobucket.com/albums/i...ps12e43788.jpg

Carbs were done by a mechanic so I hope it was done right

That is my next place to look but to get there I would have to get the console up and then the coffin lid all to get to a $5 part

I'm going to try and get a used portable tank and try that also....great idea



But hey what else do I have to do with my time

Any number of your neighbor's probably have a 6 gallon gas tank. Heck you're in Miami... if not, $20 all day long on CL. Get your Merc fitting and connect. I was able to get to my supply elbow through the starboard stern locker as its at the very back of the fuel tank.

Good luck. Portable tank before anything else. You could save yourself a lot of time and money. And regarding what to do with your time - Fiesta! Hora de celebrar el dia de la Independencia! Ole'.:cool:

I like the idea of getting at it though the starboard stern locker

I could try that before having to remove the console and coffin lid

Plan is to get up tomorrow and buy a portable tank ( my son can always use it on his whaler) and go from there

Besides that having a great time in Islamorada

Why did I take French in school?

To meet girls?????

Because you were living on the Canadian border, and thought someday you might move to Montreal :confused:

Well I rebuilt the fuel pump and no luck

Went and got a 6 gallon tank and am going to go direct to engine

I hate this!!!!!!

The idea of having to get the coffin cover up really pisses me off

No dice it did the same thing with the aux tank

Must be in the carbs?


oh well at least I have plenty of gas for the next time