1984 Seaswirl OMC running rough

Celtichawk · Sep 13, 2012

Hello everyone!, So my father and I took the boat out for its first real Sea Trial. Up the channel running obviously about 5 mph and just about 1k RPM she spit and spudder some. Just before I got out of the break wall, I stopped to chat with my fellow co-workers on the Navy Patrol boat and it dies. Shifted boat back into neutral nothing at first, thought maybe the neutral switch was messed up. After a few moments got it back up and running. We finally made our way out past the break wall and got her running up to WOT up the coast and back several miles. After about two hours into the trip she wouldn't get up to WOT easy and I had to feather the gas to get her to go. Eventually she would idle okay but spit and spuddered some.

I had to travel back into the channel about 10 miles from the open sea only running at 1.5k rpm and about 5-8mph because it wouldn't run much higher or it would die.

Any ideas what this could be, my guess is a carb adjustment needed but could the pro's chime in and if you need me to answer any questions I would be happy to answer to my best of my ability.

Boat will start up and run now at idle no problem but once I shift into gear and try to throttle her she wants to bog down and die out eventually.

Thanks everyone.

Howard Sterndrive · Sep 13, 2012

Re: 1984 Seaswirl OMC running rough

plugged fuel filter or trash stuck in the anti-siphon valve at fuel tank pickup

Celtichawk · Sep 13, 2012

Re: 1984 Seaswirl OMC running rough

Howard Sterndrive said:
plugged fuel filter or trash stuck in the anti-siphon valve at fuel tank pickup

Anti-Siphon valve so if I lift up the White round plate near motor I can reach this? Assuming that is where the fuel lines go into the fuel tank. What does it look like and how hard is it to clean or change?

Howard Sterndrive · Sep 13, 2012

Re: 1984 Seaswirl OMC running rough

I haven't seen an 84 Seaswirl, but the anti-siphon is part of the fitting where the fuel supply line comes out of the tank. Only one fuel line from your tank. Sometimes straight, sometimes 90 degree fitting like this:

Celtichawk · Sep 13, 2012

Re: 1984 Seaswirl OMC running rough

Howard Sterndrive said:
I haven't seen an 84 Seaswirl, but the anti-siphon is part of the fitting where the fuel supply line comes out of the tank. Only one fuel line from your tank. Sometimes straight, sometimes 90 degree fitting like this:

Okay I attached my picture which I believe was exactly what you shown (Howard Sterndrive) So do I just remove it completely or just buy a new one? Judging by what you show I would expect mine is exactly the copper fitting there in my picture.

Celtichawk · Sep 13, 2012

Re: 1984 Seaswirl OMC running rough

Also coming out of my carburator there is a small silver metal tube that runs from what I believe to be choke housing to my manifold, I believe. This tube does not screw into the manifold but almost has a flange on it like gas line going into carb. The other end seems as if it broke off in the manifold but has not fallen inside. Just that you can set it back in place but does not stay well.

In fact very similiar to gas line. I don't believe this is good but it can come out very easy. What is this tube and is it important or can I bypass it? I can post picture if your unsure as to what I am talking about.

Just updated this with a pic

Howard Sterndrive · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

Celtichawk said:
Okay I attached my picture which I believe was exactly what you shown (Howard Sterndrive) So do I just remove it completely or just buy a new one? Judging by what you show I would expect mine is exactly the copper fitting there in my picture.

that would be brass, but yeah - the anti siphon is likely in that horizontal piece.

as far as you pipe from the carb - that's a "heat stove" for the choke. It will work fine loose as far as getting warm from exhaust and opening the choke as long as exhaust isn't leaking out. I don't know what is loose, but maybe some wire brushing and then JB weld will affix it.

Bondo · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

Celtichawk said:
Okay I attached my picture which I believe was exactly what you shown (Howard Sterndrive) So do I just remove it completely or just buy a new one? Judging by what you show I would expect mine is exactly the copper fitting there in my picture.

Ayuh,.... Here's a novel Idea,...
Diagnose yer issue, 'n then fix it, insteada just throwin' parts at it, Hopin' ya get it right...

The Fuel Delivery issue, could be ANYTHING, 'tween the tank vent, 'n the carb...

Personally, I'd start with inspectin' the contents of the fuel Filters...

Celtichawk · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

Thanks Howard

Bond-o....Diagnose yer issue, 'n then fix it, (Exactly what I am doing) I stated to find out where to buy the part in order to replace if needed. I also took out fuel filter from carb last night and found some debris, appeared to be almost like sand but some small tiny sediments. I'm sure anything can make a difference however, I felt it wasn't severe. Although it very well could still be the cause. I will try to run her today with muffs after that and if it does not clear things up I will check the anti-siphon valve. Thanks guys, will reply if it does or does not fix.

Celtichawk · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

What is it in the anti-siphon valve I would be looking for? Just dirty and debris?

Howard Sterndrive · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

Celtichawk said:
What is it in the anti-siphon valve I would be looking for? Just dirty and debris?

anything besides 1 ball, 1 spring and gasoline, is a problem

a new one is typically $10 or so, so don't spend hours and hours analyzing it

Don S · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

If you suspect a problem in the fuel system, just hook up a remote fuel tank (outboard tank), to the engine and see if it works. Of course, if the carb is all plugged up, it won't help.

Have you removed the spark plugs and looked at them to see what they tell you? Rich, lean, broken, water on any of them?

A compression check might be a good way to find out if something mechanical failed.

Plug wires, ignition system? When was the last full tuneup?

Celtichawk · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

Don S said:
If you suspect a problem in the fuel system, just hook up a remote fuel tank (outboard tank), to the engine and see if it works. Of course, if the carb is all plugged up, it won't help.

Have you removed the spark plugs and looked at them to see what they tell you? Rich, lean, broken, water on any of them?

A compression check might be a good way to find out if something mechanical failed.

Plug wires, ignition system? When was the last full tuneup?

Spark plugs pulled, top seem normal slight white color perhaps I will snap a photo today and show you.

Compression check not done yet but yes good idea

Plug wires, ignition system has been replaced recently from original owner. I can't confirm that so if needed I can do that as well. I did though take cap off yesterday and to the best of my knowledge points, condenser, rotor all seem very new if not brand new. Wires are blue in color and very clean so unless he just cleaned them, which I highly doubt, they are new as well. Plugs seemed new too.

Take note it is running a Rochester Carburator and it's a 3.0 liter motor

This picture shows plug from cylinder 1, the rest are the same is this too lean? Also I changed the filter in carb and still same problem, will idle, sometimes a little choppy, but when I give it throttle above 1500 rpm it will go for a sec then bog right down and shut off. Starts right back up everytime with no primer.

Celtichawk · Sep 14, 2012

Re: 1984 Seaswirl OMC running rough

I know its a Rochester 2 Jet, any ideas what I could buy if I end up replacing it? I found a few places but wanted to make sure I get what will fit properly.

Celtichawk · Sep 15, 2012

Re: 1984 Seaswirl OMC running rough

Okay a update, I checked firing order and all checks out. Changed fuel filter still same problem. Today I tried to change what appears to be the anti-siphon valve on my tank, hence above pictures but threads wouldn't budge. After elbow piece there is the extended flange that goes inside rubber fuel line I will have to cut that part off in order to unscrew the entire elbow piece off. If it is not a anti-siphon valve then at least its getting replaced.

My question is if I removed rubber hose from that elbow piece shouldgas come out or no depending on if it is a anti-siphon valve. See above photo?

Second I will do a compression test and timing check next couple days.

Third talked to original owner explained him my problem and he is convinced boat needs lower unit service/shift cable adjustment or replaced. Asked how could that cause a bogging down issue sinceit does it in neutral as well meaning no connection to shift cable.

So I ask the pros if this makes any sense and if true then I suppose that's my next step after a few others.

Right now gonna try get that elbow piece off tank and replace.

Howard Sterndrive · Sep 15, 2012

Re: 1984 Seaswirl OMC running rough

Celtichawk said:
Asked how could that cause a bogging down issue sinceit does it in neutral as well meaning no connection to shift cable.

So I ask the pros if this makes any sense and if true then I suppose that's my next step after a few others.

it's a possibility - there is a module called the ESA (Electronic Shift Assist) that causes the ignition to cut out during shifts. Your original description doesn't really sound like an ESA issue, but to eliminate the ESA as a suspect, simply unplug the ESA module and go for a ride. If it runs better with the module unplugged, then yes, you need to check/adjust and maybe even replace the shift cable.

Celtichawk · Sep 15, 2012

Re: 1984 Seaswirl OMC running rough

Howard Sterndrive: Could you reply with location of this ESA? If it is what I think it is I have a new one on order should arrive monday. But a picture and location would help to determine. I can't wait to find out the easy problem to fix and get back out in the water. Want to take boat to San Diego next weekend but I may have to hold off.

Celtichawk · Sep 15, 2012

Re: 1984 Seaswirl OMC running rough

Okay correct me if I am wrong but I just realized the fuel filter I replaced was the one going into carburetor. The fuel pump on side of my motor has a filter under that upside down looking canister right? I know if that is correct you can call me a newb. I look at it this way another fix on top of replacingmy anti-siphon valve. Would bet that filter is dirty since the small one going into Carb was slightly dirty almost like sand.

I'll replace both tomorrow drain fuel and try again

Howard Sterndrive · Sep 16, 2012

Re: 1984 Seaswirl OMC running rough

just finding the main fuel filter at this point in your diagnosis, and asking where the ESA is leads us down a common path in this OMC forum.... the one where posters say to themselves:
"why buy a manual, these guys tell me everything"

Symptom based troubleshooting only goes so far and only works sometimes. If you want to have this boat for a while and continue to repair it yourself and have a reliable unit, you need to buy the OMC factory service manual and read it from cover to cover. In there you can learn how to do a complete tune-up and annual maintenance. There are important steps and safety warnings that only the factory manual provides.

Ken Cook publications (outboardbooks.com) or eBay are the best sources for new or used respectively.

Celtichawk · Sep 16, 2012

Re: 1984 Seaswirl OMC running rough

Howard: I have my manual its the Seloc version, and sorry but I could not find the ESA in the manual. Tonight I will go through it thoroughly and see what I find. As for the fuel filter I took the old one out of the fuel pump. It was a paper form appeared to be brown in color probably normal but not severly dirty but none the less it will be getting replaced.

As for the anti-siphon valve finally removed it. Turns out the tank also had a screen attached to the fuel line feeding from valve into tank. So that helps for sure to catch that loose dirt and debris.

Looking at the picture the part that is facing down with threads on it goes into the tank. I blew on that end and air came out on the other side slightly which would be the direction of fuel flow if installed. If I tried to suck from other side which is the anti-siphon side with ball and spring inside seemed to be pretty restricted. Does that make sense now and also is that normal? Would that indicate replacement needed. I will be doing so anyhow but thought I ask.

1984 Seaswirl OMC running rough

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