72 Thunderbird Formula w/twin 165hp Mercs

[Mark72233]

Video of Trying to harass Dolphins.

 

[sphelps]

I hate that ya had the motor trouble at the end of such a fabulous day .. Family and friends having a great time and the boat looks awesome !! Wish I could get out on the open water like that ... I have not gotten the nerve yet to venture out in the Atlantic very far in the MFG ..The jetties at the mouth of the St Johns goes wayyy out before ya can head to the coastline ...

 

[notlef]

Mark, Do you have Anti Siphon valves on your fuel tank?

 

[Mark72233]

You mean like a one way valve? If so no I only have shut off valves on each line. There is one feed line coming from the tank, I think it is a 3/8" line. At the bilge it tees off to both engines with again 3/8" lines where it goes into the water separators attached to each engine before it goes to the individual mechanical fuel pumps on each engine and solid lines running from the pumps up to the carburetors.

 

[Mark72233]

See if this picture attaches. Something like this at the shut off valve so one engine doesn't try and pull from the other?

 

[Mark72233]

A couple of more pics from yesterday of me and my nephew, Ari leaving one of the city marinas.

 

[Frey0357]

Wow! Congrats Mark!! The boat looks beautiful! great pics..

Frey

 

[notlef]

See if this picture attaches. Something like this at the shut off valve so one engine doesn't try and pull from the other?

Yep, That's what I was asking. They are there to keep fuel from spilling into the bilge in case of a leak. My boat has twin 5.7 Crusader's and I have was having fuel issues like you are describing. The Anti Siphon valves were the culprit.
Found this out after rebuilding the carbs twice, replacing fuel pumps, filters, lines. Was in the process of replacing the main lines from the tank to each motor. when we found them. Took them off to test and problem went away. It doesn't take much for them to fail. I keep several set of spares on the boat now.
It's possible you could have debris in the valve that is not allowing it to open all the way.

 

[Mark72233]

Ok I don't have any anti syphon valves on the system yet but I did order 2 of them. I will pull everything and check for trash. The fuel tank and lines are all new not that there still couldn't be trash in a new tank, fill hose or supply hose.

 

[nurseman]

Do you think that the main line before the tee is big enough? I'm not super mechanical, but that seems like a small line to feed 2 engines with. Just a thought.

 

[Woodonglass]

Well....It's looking like the OFFICIAL Splash should be coming pretty darn soon!!!!

 

[Mark72233]

Yep I think with the family on the boat and a good day until they quit again I will have to call Monday the official Splash day and still forgot to get a picture in my Splash Shirt.

Nurse that is what I was thinking until yesterday after going from the city marina out to the gulf and back twice and that's a 3-4 mile run one way at 2800 RPMs and not even a hiccup from either engine. Here's my theory right now and I didn't get a chance to work on the boat yet, anyway. The fuel pump that was on the starboard engine when it quit is now on the port engine when it quit there after working for the day. Than I think since I don't have any anti siphon valves it sucks air from the side that quit working and the engine had enough fuel in the carb bowl to get me back to the dock before it went dry so let me buy one pump and replace the one on the port engine and install anti siphon valves on both engines. I think that will solve these gremlins.

 

[alldodge]

Agree you want the antisiphon valves on, but the valves due create a bit more restriction for the pump to pull through

 

[thomas15]

Hey Mark
Great job, the boat looks amazing!
I joined this forum in August of 2014 and have read and kept up with this thread since that time. You make it look easy and while I know it's not, in a few years when time is more available to me I hope to have a project and thread of your caliber.

Steady as she blows Captain!

 

[Mark72233]

Question for you electric fuel pump guys. I have ordered two of the Holley Red Marine electric fuel pumps and they should be here next week. I am sure they come with instructions on how to wire them but how would you guys wire them. Where would you place it, after the water separator and in line filter just prior to Carb and I read some where they should be place below the height of the fuel tank but if I do that it puts them pretty low in the bilge and near any water that is in the bilge.

 

[alldodge]

Holley recommends to put them at or below the tank exit to put less strain on the pumps. The pumps go after the water separator filter, which can be higher but again low is better. Basically after the filter and pump are full of fuel there won't be much of a lift problem for the pump do to lines all being full, and another reason for the anti-siphon valve at the tank.

I would use no more then one filter inline, but the one on the carb inlet is not an issue.

I would add a Tee to the oil pressure port and add a 3 prong switch and wire like the pic below.

Do you have 3 or 4 terminals on your starter? (2 large, and 1 or 2 small

 

[Guest]

Mark:

Holley makes a complete line of 12V marine electric fuel pumps that you can retrofit to your Mercs. These are commonly used on GM Vortec small block V8s because the block castings for the mechanical pumps are closed up. I would google Holley marine fuel pumps to get the best price.
I'm sure there are other makes, but I've used these in the past with good results.

 

[Guest]

Oops, didn't finish reading the thread, you already have Holley Red pumps

 

[Mark72233]

Yep they should be here next week and for now what I did was buy one automotive fuel pump for $16. I know you aren't supposed to use them but it was a cheap way to diagnose the issue. I also had a in line anti syphon valve so I stuck it on the port side. So after I installed new fuel pump on the engine that quit first that I think has the bad fuel pump it cranked up pretty quick and ran perfect. The other engine also cranked up after a few minutes of cranking and priming the carb. Ran both on the hoses and perfect. Took it back out to the Bay and they ran great so loaded everyone up and headed back out. Ran it out to the gulf again and again it was flat enough to anchor on the gulf side and enjoy the secluded beach for a couple of hours than ran back to the jetties and there was about a dozen Dolphins showing off for the group gathered there on charter boats, private boats and the dozen or more jet skis. Kids had a blast and Dolphins love to stick their heads out of the water near the boats and the kids and tourist scream and yell and oohhh and aaww which the Dolphins react to. They like being around people as much as we like being around them. Than took a run in the Bay for sight seeing and exploring. Boat engines have another 3 hours on them and no issues this time.

 

[sphelps]

That's great news !