!972 Seaswirl Questions

I have a couple of questions regarding my OMC 120hp Seaswirl. I read this site almost veryday becasue Chief helped me solve some problem previously.

#1: I have finally taken the time to figure out where a small leak is coming from on my boat. I found water in the bilge when there really should not be any. I am getting the carb re-built so we thoguth the water was from the manifold. I pulled the manifold and have found waht appears to be a hairline 3" crack along the rounded edge. I think this can be welded. I just wanted to know some of the best options. I don't want it to get worse. The boat is stored in doors and we don't have exteme weather here.

#2: The fuel filter is above a relay on the drivers sdie of wengine above the mechanical fuel pump. This seems like inviting disaster. My friend recommends getting an electric fuel pump and adding a glass viewable inline filter attached at the transom. I think the fuel filter idea is great. I am not real keen on the electric fuel pump. What I would like to know is recommendations for a particlar type of sighted filter that removes water as well. I am also going to be removing the steel lines and going to rubber from the filter to the carb. Also could you maybe chime in on the pros/cons of electric fuel pumps. I would like to maybe approach this particular issue in December when it is less condusive for me to go out.

Thanks for your help......

Merced Glen

mercedglen said:

a hairline 3" crack along the rounded edge. I think this can be welded. I just wanted to know some of the best options. I don't want it to get worse. The boat is stored in doors and we don't have exteme weather here.

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At some point, that boat was in extreme weather. That crack was likely caused by ice.
You can vee the crack out with a dremel tool or die grinder, and then JB weld or other epoxy product to fill it in. But, be aware you are risking the engine. It's your call as to how serious you feel the crack is and how many years are left in a decades old manifold. The professional in me says toss it and buy a manifold. I have repaired manifolds before, but only when they were obsolete and no replacements were avail.

mercedglen said:

#2: The fuel filter is above a relay on the drivers sdie of wengine above the mechanical fuel pump. This seems like inviting disaster.

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how many disasters did it cause from 1972 to 2012?

hystat said:

how many disasters did it cause from 1972 to 2012?

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Actually none....I had a problem while out and about in it where I needed to open the fule filter and fule of course came out. I was a little concerned about an electrical caused fuel fire.....Just asking I guess. The point you made about the crack is something I will ponder. If had unlimited funds I would just purchase a new manifold but I don't hence the 40 year old boat which I know is a whole you put money into but I don't have to sink money into something that may have another solution.....

that's why I said it's your call. no one can step into your financial shoes, or know your risk tolerance, or see the crack. I don't like replacing parts that don't need to be replaced. I just wasn't sure if you knew that a 40 year old manifold is already 30 years older than OMC engineers ever dreamed it would live. If it is or does crack internally (between water jacket and exh or intake port) it can damage the engine.
That's why I suggest JBweld/epoxy. You don't want to start welding or brazing on 1972 castings- that would be asking for more cracks. And if one day you're running along and the engine hydrolocks and pops a con rod through a piston, you will have no remorse. It's all about educated risk taking trying to boat on a budget. That's why I gather spares at every opportunity.

It's not about unlimited funds, but measured risk. Don't risk an engine without knowing the risk.

All very good points that I haven't complelely thought about, hence I am here. So I am thinking JB Weld or Marine Tex or some other recommended external epoxy. I will try and post a picture of what appears to be hairline crack. What I am concerned about is getting the materials to stick to the substrate, in this case cast iron. Is there a chemical like acetone that would clean the surface sufficiently so that the substrate would be more likely to bond with the epoxy ?

I will of course look for a possble used manifold. There is a company in Sacramento called shipwreck marine that might be usefull in this search. I am a little hesitant because as you say the manifold is quite old although it does disturb me thinking that the part was designed with a life cycle of ten years.

Unfortunately we as a nation have learned that leveraging funds without some type of liquidity is quite often more of a risk than previously imagined but then we are talking a $280.00 manifold. I may start putting some money away for a newer one too.

What are your thoughts about inline sighted fuel filters. I see you have answered my electrical concerns. I actually see no reason to change from mechanical to electrical fuel pump at this time unless of course someone can demonstrate something tangible in doing so.

I appreciate your response and I think I ahve learned a little more today......

grind it down to bare metal, and JB weld sticks like snot to a vest
another trick is to drill a tiny (1/8" or 3/32") hole at each end of the crack - it relieves the stress and a circlular hole the drill makes, helps to stop the crack from progressing.
Manifolds are unpainted cast iron inside. 5 years in salt water, 10 in fresh is the recommended replacement.
$28/year not so bad
If you go with a full closed cooling systems on a new engine, the manifolds will live 30 years no problem.

There's no point in designing them to last more than 10 years because, like yours, many fail due to improper winterizing.

If it were me, I'd save money by forgetting the "reinvent the fuel system" idea, and put it towards a manifold.

$250 here:
http://www.boatbandit.com/manifold-omc-3958.aspx

Well, I am going to go ahead do what you suggest. I will try the epoxy route and then save some money for another manifold. I think I can make this work through the next six months. I had an electronic ignition installed and now the two barrel is being re-done. We checked the timing on the water and the boat really gets going even better now. I would expect after everything being done it will run very well.

Hi Mercedglen I had a similer problem with a manifold buildup in the water jacket creating a hot spot. I couldn`t get at it so I drilled a large hole, cleaned out the restriction, fabricated a stanless steel patch and with the help of high temp silicone it worked great. But as Hystat said be very carefull as this is old equipment and you have no way of knowing when the inside will start leaking but this gave me the use of my boat untill I hat time to call in a few favors and repower . If you know the right people with connections you can get new long blocks for less than rebuilding.