I was out saturday morning,and the boat was running awesome. After fishing till slack we decided to make a run to get more pogies. After running about 10 minutes at 17 knots we are entering the area we want to be in, and all of a sudden the boat drops to like 1500 on the tach and the speed slows down. No alarms, so I throw it in neutral and she is idling fine, throw it in gear she takes off like normal and gets up to around 4000, and then does the same thing. I check the aspirator bulb and she is soft while the engine is running, not sure if this is status quo or not, so I squeeze it, and it won't inflate itself. So I am thinking something is going on here. I pop the inspection plate, a look see at the tank and it appears that the vent hose is cut, so I am thinking a piece of the hose fell in the vent opening?? So we make our way back to the ramp at about 5-6 knots, and once we get into the river she dies. While we are floating there I pop the engine cover off, and remove the fuel filter on the engine, when I did this I heard a whoosh, and the screen looked clean, so I put it back together. I then checked the primer bulb and it had re-inflated, so I am thinking if there was something stuck on the pick up screen in the tank, when I opened the filter it release the vacuum and it just came off. I prime the engine the bulb gets rock hard and she starts right up, so I mosey in at the no wake speed with out issue. Today I checked the vent hose, there was plenty of slack, so I took it off and cut it back and put it back on with new clamps. Then I looked at the cut and it was just the outer covering, not through. I put it on the muffs and primed it up and ran it for a bit and everything is hunky dory. I am now thinking run out the fuel, pull the sending unit and try and check the tank. Not sure what else to do right now, but this crap has got to end or it will be a Viking funeral soon... :wall:

Wait.... you got pogies down there????? We have none....:smash:

Wish I could help you, Bill, but a mechanic, I am not.....

you have what is called high vacuum issue. your vent could be clogged. check the outside parts and make sure it is clear. the other thing that causes this is the pickup tube(where you draw fuel from the tank) usually has a screen in the bottom of it. these screens tend to get clogged with debris that ethanol fuel cleans from the inside walls of older tanks. pull the tube out and remove the screen. you don't need it. while your in there probably wise to replace your anti-siphon valve. the reason it would run low speed is that once you slow down whatever clogged the screen fell back into the tank and no more clog. more likely to happen at high speed

Thanks Freebie, I am off tomorrow so I will pull the sending unit and check the screen.

Thanks Freebie, I am off tomorrow so I will pull the sending unit and check the screen.

the screen is not in the sending unit. the sending unit if for your fuel gauge. the pickup tube is where the fuel comes from. it should un thread from the tank. make sure you use thread sealer when you put it back together. how did you make out on your waterpump thermos?

Waterpump no problem, thermos have not attempted it yet. The two outside bolts look tough.

Is the screen at the top, or on the bottom of the tube? In other words where the nipple with the hose barb threads in, or the fitting it self that the barbed part threads into?

Waterpump no problem, thermos have not attempted it yet. The two outside bolts look tough.

Is the screen at the top, or on the bottom of the tube? In other words where the nipple with the hose barb threads in, or the fitting it self that the barbed part threads into?

it's not hard you need stubby wrenches, a deep socket set and a prybar

Waterpump no problem, thermos have not attempted it yet. The two outside bolts look tough.

Is the screen at the top, or on the bottom of the tube? In other words where the nipple with the hose barb threads in, or the fitting it self that the barbed part threads into?

you need to unthread the square block from the tank itself. take out the hose barb and then you can get a wrench on the other part. should be 9/16 for the hose barb and 7/8 for the tube. the screen is usually at the bottom of the tube

If the bulb is collapsing you are:

A) pulling a vacuum on the tank as the vent is clogged, this could be temporary cured if you open the fuel fill and allow air inside. (be careful no water gets in there)

B) as mention, your pick-up is clogged with tank corrosion stuff. If you have a fiberglass tank and an older boat, this is most likely your problem. This could become a chronic problem. If so, take off the screen on the pick up, and put a pair of RACORs on board with a lever switch so you can change the filter on the fly and change the cartridges several times a season. (then consider selling the boat or changing the tank to AL)
If the tank is AL and it is old it could also be the problem. You will need to open the tank, inspect and de-fuel it. (filter the fuel out and put it in your truck)
Ethanol has caused more marine fuel tank problems than you can count.

C) maybe you just got a bad batch of fuel with bunch of crud.


BTW, if you have fuel injectors, you DO NOT want this crud to reach them!! You might be looking at more serious repair expense. Keep that fuel clean.

That crap was on there good, the wrench stripped the barb, so I put a vice grip on it and it snapped off at the threads, then I got the tube out.

Bad news is no screen on the end of the tube it was cut like a birds mouth. I am going to get a new tube and barb I am going to run out the rest of the gas on the muffs a little here and there every day, then maybe pull the sending unit and try and look in and get out any debris. I also changed the vent, the old one was corroded , but clear of debris, I will also blow out the hose with a compressor while I am at it.

Isn't boating fun?

Upon further inspection of the pickup tube I found something, the screen was at the top of the tube, when looking through it towards a light there was very little light shining through.

So I took the old tube apart and this is what I found, there was some stuck in the tube....

I put in a new tube with no screen,and antisiphon hopefully I will be good to go..

On my old boat I found this when i drained the tank

http://www.syncboard.com/albums/Boat-Tackle-Box/Picture_025.sized.jpg

Upon further inspection of the pickup tube I found something, the screen was at the top of the tube, when looking through it towards a light there was very little light shining through.

So I took the old tube apart and this is what I found, there was some stuck in the tube....

there you go...looks like the culprit. as long as you have a racor in the boat you'll be just fine. if not I would put one in before you run it or that will end up in your carbs.

The anti siphon valve ( your hose barb) is the #1 culprit when that symptom occurs.. being made from aluminum, the gasoline/alcohol corrodes the inside of the fitting, thus impeding the moving of the check ball... all that crap in the screen is another by product of the gasoline... as others have stated, protect yourself with a good cartrige type fuel filter...

The anti siphon valve ( your hose barb) is the #1 culprit when that symptom occurs.. being made from aluminum, the gasoline/alcohol corrodes the inside of the fitting, thus impeding the moving of the check ball... all that crap in the screen is another by product of the gasoline... as others have stated, protect yourself with a good cartrige type fuel filter...

That actually looked very clean and shiny on the inside, but I ended up with a new one anyway.

yes, they can appear clean and shiny on the inside ( the ball is stainless and we all know how well aluminum ans stainless play togehter) and still "stick" it's always a good starting point.... I replace mine every two years when I re register the boat, I also change the fuel pump, thermostat and water pump at this time.... cheap maintenance for a potential headache... Hope it all works out well for ya....