Fuel Line does not hold a prime

[SlickNick]

Hey all,

Brand new to the forum and owning a SeaRay as well and I could use some guidance from all the seasoned owners on here. So here goes: I recently acquired a 1988 Sea Ray Seville 16 Bowrider with a 100hp Outboard on her. The boat sat for a year in my buddy’s driveway collecting dust and rainwater. Before he owned it, it was very well taken care of and maintained, by my reckoning and inspection anyhow. So when I got the boat from him, I replaced the battery in it and the thing cranks over perfectly. But I can’t get it to start. Two things to check, right? Fuel delivery and spark. Without all the mundane details, it has spark and fires. Fuel delivery is the problem, as it won’t hold a prime. Do these boats have a check inside the inline fuel filter? I’ve gotten as far as taking it over and it blows straight throw both ways. So I’m figuring if the filter doesn’t have a back flow check then the pump diaphragm must be bad. Any suggestions or pointers would be greatly appreciated, as well as a shove in the right direction as to where to get parts for this thing! Thanks all!

 

[dlvwill]

Spray some starting fluid down her to make sure it will fire on that to confirm fuel issue.
Probably need to go through the carbs as they are likely gummed up and clogging the jets if the fuel wasn't treated.

 

[Lazy Daze]

Aside from the things you mentioned...

-- Clogged fuel tank vent
-- Cracked/clogged pickup tube
-- Failing (internally) fuel lines
-- Failed primer bulb

Try running with a portable tank and new fuel line to eliminate/prove that side of things. Taking the gas cap off eliminates a clogged vent as a possible culprit, as well.

 

[SlickNick]

Thanks for the input. Let me elaborate on what I did last night. Dusted the carbs with fluid. She’s fires great and sounds healthy. Ran a portable tank with new gas and used a hand suction pump to get fuel up to the filter. It drains back down the line. I’m thinking the fuel hose connection maybe bad and air is getting in and causing the back flow. Is the filter supposed to prevent backflow?

 

[scoflaw]

No clue what engine you have , but the 2 strokes have low pressure pumps that feed the carbs and work off cylinder pressure. They have an internal diaphragms that do wear out. My Yami 2 stroke has a 1 way valve in the mix as well

 

[dlvwill]

When you say hand suction pump do you mean a primer bulb, or something else you have rigged in there?

A primer bulk does have one way checks, the fuel pump would be where the next check is, but you need to maintain fuel up to that point. The engine fuel pump needs liquid to pump.

 

[SlickNick]

Thanks dlvwill and scofflaw. You just answered it for me. It’s a 100hp merc elpto. No primer bulb. Meaning the diaphragm is most likely shot. $15 part. Thanks guys!

 

[SlickNick]

Ok. So anybody know where to get a diaphragm kit for this thing? I’m having trouble finding the right one. The fuel pump is part #98766-C1. 1988 Merc 100hp OB I’m assuming the part number is antiquated and has been replaced with a new part #. Any help in the right direction is appreciated.

 

[SlickNick]

 

[Lazy Daze]

Probably the easiest/fastest way would be to call a local Mercruiser shop - they can do the legwork for you and figure out what you need.

 

[techmitch]

Ok. So anybody know where to get a diaphragm kit for this thing? I’m having trouble finding the right one. The fuel pump is part #98766-C1. 1988 Merc 100hp OB I’m assuming the part number is antiquated and has been replaced with a new part #. Any help in the right direction is appreciated.

Hope this helps. https://www.wholesalemarine.com/mer...VApQhfFVa33syPlpua8alRE3kukR4NeRoCI7wQAvD_BwE
Read FAQ on this one. https://www.go2marine.com/item/99816/fuel-pump-kit-18-7818-1.html

 

[Thornton69]

Does it not have a hand prime bulb on the supply line? As someone else mentioned, it alone should stop the fuel from running back to tank. Maybe I missed something, but I would start with replacing it. With a helper, you should be able to run it with just that if unsure about the merc pump.

 

[CNYBoater]

when I have multiple items to buy online for my outboard I tend to use http://www.marineengine.com/ to look up my engine. that gives me the parts diagrams to see what the original through current era part numbers are. I then search all the parts going back to the original to see who online has a new old stock part available, and which is the best deal. Quite a bit of the time its that same website when you factor in the flat rate shipping for multiple items. I also you a local marine repair/store near my lake. Guy is a bit of a curmudgeon, but so am I, and I'm supporting a local business. A lot of times, he's giving me the same price as online and his markup is pretty close to what shipping would have cost me anyways.

 

[SlickNick]

Ok guys. I rebuilt the fuel pump. Easy job and that was the problem. Boat is now running but I have to throw another one at y’all, and forgive me if I sound like a newbie, cause I am, but I need to know what part this is so I can get a gasket set for it because it’s leaking. thanks in advance!!

 

[SlickNick]

Figured it out! It’s the pump accelerator!! $26 at boats.com!!