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496/Raylar HO600 fuel questions

Old 07-06-2017, 05:39 AM
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Originally Posted by BUP
Another reason for fuel pressure bleed down is a stuck open and or injector(s) the pintle can not fully seat close.

Or a fuel pump check valve issue
Thanks BUP. Added to the list for the mechanic to check .
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Old 08-25-2017, 03:12 PM
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Ok so a month has gone by and Ive had very little time to sort the boat. Mechanics findings were that the fuel pressure is all over the place, sometimes as low as 35psi, sometime shoots over 70psi, probably lucky the engine is still in one piece. Apparently the regulator in the cool fuel module isnt a standard part. Hes messed about for hours and Ive ran up a massive labour bill, and got nowhere...

So have done some research into an external pump and return line system to hopefully solve these issues and simplify things in future. Availability of the parts in the UK is quite important. Can get some Aeromotive parts here and there, no Weldon parts anywhere.

Have seen the Fuelab pumps and regulators, they have a transducer in the reg and variable speed system for the pump so it will slow down when the fuel demand is lower so less return to tank and less heat. Cant find any mention of this system on a boat but it looks like it will work. Unless anyone has any info why I shouldnt go for this system. Idea is to get the fitting welded to my fuel rail the same as Keith Atlanta above. I have a supplier for Fuelab parts less than 20 miles away.

Some more questions if you lot dont mind...
  • Existing fuel line between tank and Racor fuel/water separator is 1/2" ID and uses 1/2"npt fittings, can I still use this line and filter?
  • If so the Racor filter inlet is about 10" or a bit more above the level of the tank, does this need lowering down into the bilge?
  • Im hoping the Racor 10 micron is good to be the filter that is needed before the pump? Then I will fit an inline filter after the pump to catch anything the pump spits out...
  • What size lines to go for? thinking AN-10, but is AN-8 sufficient for my engine? I only want to buy one set of tools for making up the lines. so would use the same for everything, supply and return.
  • On the electrical side, will the fuel pump relay on the engine designed to run the two cool fuel 3 pumps be sufficient to run this new pump or do I need to upgrade this also?
Once again thanks for any help.
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Old 08-25-2017, 04:45 PM
  #13  
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Your wording is not clear, did he or didn't he replace the regulator in the fuel module ? Open up the module to see if a bunch of crap and paint peeling in there ?
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Old 08-25-2017, 04:51 PM
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He did not as he doesnt believe he can get hold of the right one. The one that came with this engine looks different to the stock regulator.
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Old 08-25-2017, 05:19 PM
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So what was he dinking with ? I'm just asking.
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Old 08-25-2017, 07:16 PM
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If you do a custom fuel system, look into the Russell quick connect fittings for GM LS engines. I can't tell you if they will work for the 8.1 fuel rail, but there is a good chance they will. Obviously, a weld on is another choice too.

Russell Push-On EFI Fittings 644113 -6 AN Male x 5/16' SAE Quick-Disconnect Female

Russell Push-On EFI Fittings 644123 -6 AN Male x 3/8" SAE Quick-Disconnect Female

Russell Push-On EFI Fittings 644133 -8 AN Male x 3/8" SAE Quick-Disconnect Female

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Old 08-25-2017, 07:17 PM
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Sorry, there is no 'size' thing on the toolbar to make those letters smaller. Doh !
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Old 08-26-2017, 06:24 AM
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Originally Posted by SB
Your wording is not clear, did he or didn't he replace the regulator in the fuel module ? Open up the module to see if a bunch of crap and paint peeling in there ?
Both Raylar and Marine Industries West sell adjustable fuel psi regulators that fit in the stock Merc gen 3 cool fuel module. Around $200.

I would have a competent mechanic check It out before redoing everything.
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Old 07-10-2018, 05:20 AM
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Hello everyone. I thought it right to return with some info as you were all helpful with your suggestions.

Firstly I ditched the previous company that was doing work for me, I wasted so much money and lost a summer of boating to their BS. For example they billed 5 hours messing with the fuel pressure as they couldnt prime it then billed two hours for 'internet research and sending emails', tried to bill £200 for a 20 minute job welding the fuel fitting to the rail as Keith above has on his (I removed from the engine all they had to do was the welding) as they had had to go out and get a pack of TIG wire... at which point I kicked off and parted ways with them.

I installed a Fuelab fuel system with variable speed pump and regulator which works amazingly returned to a fitting in the fuel fill hose into the tank, boat ran better for a while but not perfect. Some other issues then crept in. Researched myself every time and learned a hell of a lot about engines. Found previous mechanic had broken an ignition lead leaving me on 7 cylinders, installed wrong spark plugs, when I asked them to flush the coolant system as the pink colour was starting to fade they had just replaced what was in the tank, it quickly changed back to faint pink again, both block plugs were seized so no chance this was done properly, sea water pump impeller had been changed but the housing was destroyed with scoring so I had a nightmare priming the water system whenever I launched bleeding sea strainer and pump etc, now has the nice Hardin stainless pump which isnt too bad to install now the cool fuel unit is gone, the priming is now a non issue and water pressure is perfect.

Reached the limit of my ability with the repairs and have now found a new company to take the engine issues on which isnt easy in the UK but they seem passionate about performance boats and getting the boat running to its full potential, most importantly they have the correct scan tools needed which the previous company would not invest in.

In the last few weeks an issue was found in the fuel tank, fuel pickup tube was replaced before I bought the boat and the small gause filter from the old one was still floating around in the tank, every now and then this would be sucked into the new pickup tube restricting flow, now this is gone the fuel pressure is perfect. Other issue was the ECU was potentially damaged and unable to be read correctly, after speaking to Raylar it was suggested we replaced the ECU so I went for it and now it is like a new engine.

So now this is all fixed and boat is now running well sitting at 75mph with possibly more to come its a shame that I now still cant use the boat as there is a tapping noise developing near the back of the engine that is being investigated this week. Hoping something small on the top end as the old ECU only read around 150 hours for this engine.

Once again thanks for everyones suggestions and the knowlege I have taken from searching through this site.
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Old 07-10-2018, 07:06 AM
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Originally Posted by SB
Sorry, there is no 'size' thing on the toolbar to make those letters smaller. Doh !
Originally Posted by Ryan00TJ
Both Raylar and Marine Industries West sell adjustable fuel psi regulators that fit in the stock Merc gen 3 cool fuel module. Around $200.

I would have a competent mechanic check It out before redoing everything.
Wow! I love the charge for "internet research".
Sounds like your on the right track now. Modified setups generally live up to the BOAT name of Bust Out Another Thousand!

What did you end up setting engine off fuel pressure at?

Last edited by Ryan00TJ; 07-10-2018 at 07:25 AM.
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