Final Idle Fix ??

BMILLER · Post by **BMILLER** » Sun Aug 19, 2012 11:19 am

After having the starboard engine not even wanting to start at all now, I've replaced the metal inline fuel filter, added a new 10 micron canister filter as was recommended to me on this forum, replaced the fuel line from the fuel pump to the distribution manifold back at the transom with marine A1 3/8" fuel hose and am waiting on the arrival of a 1409 carb which I ordered. I can only HOPE this finally fixes this starboard engine woes. After researching the old service records this carb (engine starting and idle) has been problematic for a long time. I can only hope this is the fix and not a fuel tank issue...................... and going to replace the vent hoses too.

Vitaliy · Post by **Vitaliy** » Sun Aug 19, 2012 11:36 am

have you attempted to fire the engine off with just ether? i had a similar issue and to make sure it wasn't the engine i just put some fuel into the filter unit (fill the bowl fairly much) and just jump the engine while spraying ether, if it starts then its the tanks or the lines, (it should run for a minute or two with just that gas)..... if it chock's then its the carb...

larryeddington · Post by **larryeddington** » Mon Aug 20, 2012 10:04 am

Barry, you are not going to like dealing with the vent hose. It is under the floorboards and goes up the outside bulkhead. Ergo possible furniture removal to get boards up and outside verticle board. I know cause mine is all open and easy now.

You are welcome to come and study it anytime.

BMILLER · Post by **BMILLER** » Mon Aug 20, 2012 5:10 pm

Good point Larry........I'll check the condition of the vent hoses and make sure my vents are not filled with mud daubers, then address as needed.

As for starting with ether, I respectfully pass on that one. If I coax and coax the thing and hold the throttle at 3/4 open, it may start but screams for an instant till I can back it down. If I then set it at a very fast idle it tries to run but roughly, then may suddenly die again. Soooooooo, new inline filter, new 10 micron fuel/water seperator, new 3/8 A1 rubber hose to inlet side of fuel pump and a new 1409 carb. If that doesn't fix it..........................?? It started fine all winter long...........one 3/4 throttle to set the choke and then just above idle to crank her over and she started right up. Ran the engines every week to bring them up to temp, etc. Started having the problems in the spring. Yup, it has Marine StaBil in the tanks. Port engine starts fine. Boat will stay a dock queen for a while, horn and lights not wired up to the new system yet. Better half is "urging" me to sell it. It may come to that.........who knows ?

75 Tri Cabin · Post by **75 Tri Cabin** » Mon Aug 20, 2012 6:17 pm

If your vent hoses are plugged it will run longer than what you are saying, before it will shut off. |If you want to eliminate the fuel system take a 6 gal outboard tank with good fuel and hook it to the fuel pump and start it. It may have a vacum leak at the carb base. Try to close the choke while running, if it picks up speed then you have a lean problem. Either vacum leak or lean carb. Have you tried adjusting air idle screws on carb? Start with screw them in all the way and back off 1 turn then go 1/4 truns either out or in from there. You will hear the engine pick up or want to die, adjust till smooth. Also check the antisiphon valve on the tank. They love to stick after winter. They will open not all the way and cause problems with fuel flow.

larryeddington · Post by **larryeddington** » Mon Aug 20, 2012 6:52 pm

I agree using a smaller above deck plastic tank will eliminate all other problems. I have a 6 gallon one to use for starting my twins on the hard.

BTW My f28 did not come with anti syphon valves, I dissassembled tank fittings and nada. The new tank system will have them. I have two shiney bran new ones to install.

BMILLER · Post by **BMILLER** » Mon Aug 20, 2012 7:33 pm

Thanks. All good points. BTW where is the location of the anti siphon valve? How can it be accessed. My interior is all out anyway, but all flooring is still intact, but there are access holes and panels..........and I can sure add some more if necesary

Big D · Post by **Big D** » Mon Aug 20, 2012 8:20 pm

Anti-siphon valves are right at the tank where your hose is fastened to. It will look like a regular fitting. If you suspect the vent, simply remove the gas fill cap and it will vent the tank.

Before going with another carb, the good thing about having twins is that you have 2 of everything. Swap the carbs and see if the problem follows the suspect carb, and running on a portable tank as suggested is the best way to isolate the ship's fuel system but do only one thing at a time so you find out which change fixed the issue.

BMILLER · Post by **BMILLER** » Tue Aug 21, 2012 11:41 am

I have a Carter remote mount electric fuel pump here in the garage. I should probably set it up on the dock (away from the boat) on a stand w/a battery and pump out the fuel from that starboard tank and then pull the sender and take a look inside with my LED flashlight. I'd run the fuel into 5 gal cans. Unfortunately that tank is about half full.............

I hate working around "empty" tanks. Just have to turn off ALL AC and DC power and pick a windy day. If it has debris in the tank, how do you clean it out............a rag on a stick? At least there is an existing inspection door for the sending unit next to the air conditioner. Might take the air compressor along and back blow the fuel line too. Maybe the original fuel line is blocked? BTW, is that tank outlet and anti siphon valve on the bottom, top or end of the tank. I've never peered into that area....yet? Then after all that, perform a smell test for fumes, air out as necessary then run the blowers for a while just to make sure its OK.

aweimer · Post by **aweimer** » Tue Aug 21, 2012 11:55 am

Big D wrote:Anti-siphon valves are right at the tank where your hose is fastened to. It will look like a regular fitting. If you suspect the vent, simply remove the gas fill cap and it will vent the tank.

Before going with another carb, the good thing about having twins is that you have 2 of everything. Swap the carbs and see if the problem follows the suspect carb, and running on a portable tank as suggested is the best way to isolate the ship's fuel system but do only one thing at a time so you find out which change fixed the issue.

Good point... swap carbs and or test/remove/clean anti siphon valve.

larryeddington · Post by **larryeddington** » Tue Aug 21, 2012 12:08 pm

Barry assuming you have round tanks the fuel pickup comes out on the top right beside the sending units. There is a manual cut off valve there but nev er found any antisiphon valves. The access ias located in a round cut out under aft bench beside door.

aweimer · Post by **aweimer** » Tue Aug 21, 2012 12:59 pm

They look like a normal fitting but they are not. Its the top side of the 90 coming out of the tank. Wish i had a picture. It doesn't look like anything but a female/male connector.

larryeddington · Post by **larryeddington** » Tue Aug 21, 2012 2:12 pm

I have 2 new ones and know what they are and look like.

Putting new tanks in mine removed old ones scrapped all fittiings and pipes. My F28 did not have anti siphon valves but will.