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-   -   502 mg problem.. (https://www.offshoreonly.com/forums/do-yourself-boating-budget/369683-502-mg-problem.html)

lear60man 12-12-2020 07:04 PM

502 mg problem..
 
Self described shade tree mechanic and here is the problem. Went out today to do a dry run on a upcoming Christmas parade route that was 2.5 hours at idle. At about 2.75 hours at idle, the Stbd engine started to sound like the power steering pump was failing so I gave it a little throttle to investigate and the engine didnt respond. In fact, I goosed it and got nothing but idle thrust until it died a few seconds later. Would not restart. Limped home on the other engine. Gauge readings normal IE Oil Press, water temp.

It attempted a few restarts, and the engine fired up, hung at idle for a second or two then died. Tried this 2-3 times and now it wont even fire. I can hear the electric pump prime when I turn on the key. I opened the drain plug on the Racor water fuel separator to drain it, unscrewed the white oil filter style fuel filter and drained it to look for contaminates or water (None). So out of panic, I ordered a new Quicksilver fuel filter and fuel regulator. I read up on some old threads about vapor lock with VST system and dont know if this applies to me or not.

Anything i can try to get this thing up and running for the boat parade on Dec 19 would be appreciated. Im all ears for tips and tricks about what to try and test. Will the ol, pull the air cleaner and spray in carb cleaner trick work to confirm fuel delivery? Im thinking fuel but........?

1996 Mercury 502 Mag MPI stock but rebuilt 20 hours/10 months ago.

Eddienel 12-12-2020 08:23 PM

How old is the fuel line? Pump? Fuel filter? Ive seen where the inner lining on some fuel lines will collapse. Also I would check to see if the Pump is actually putting out. You dont want to do brain surgery to cure a cold. Start with the easy and work your way up.

lear60man 12-12-2020 09:33 PM

The motors were rebuilt about 10 months ago with new bolt ons including new filters etc. Could they have reused fuel lines? Possible, but all the spendy bolt on components were new at time of rebuild so it wouldnt make sens to reuse cheap hoses.....but I could be wrong. I assume the fuel flows from the front of the engine to the electric pump towards the back of the engine? Ill pull the rear fuel line in the AM and have the wife crank it. Ive done some reading that this motor might have a mechanical fuel pump (lift pump) that delivers fuel to the electric pump. Correct?

Fuel is about 3 weeks old as I take her out a few times a week.

Crude Intentions 12-13-2020 12:50 AM

The mechanical pump would be on top of the sea pump. Just pick up a pressure gauge and put it on to check pressure. Sounds like the cape parade.

also maybe try swapping iac and tps with other motor. Could possibly those

AllDodge 12-13-2020 06:46 AM

What is the engine serial number?
Right now, don't know what configuration the motor is. I read VST, but being a 96 it would probably have cool fuel

When the canister filter was removed, was the filter full of gas or was it low?

lear60man 12-13-2020 12:36 PM


Originally Posted by Crude Intentions (Post 4769054)
The mechanical pump would be on top of the sea pump. Just pick up a pressure gauge and put it on to check pressure. Sounds like the cape parade.

also maybe try swapping iac and tps with other motor. Could possibly those

After going over some pics of the engine, I dont believe Ihave them. If a mechanical pump is connected to the raw water pump...then thats a big negative. TPS.. Thats an easy one to swap from the other engine to test, thank you. IAC another easy swap to confirm or rule out.


Originally Posted by AllDodge (Post 4769060)
What is the engine serial number?
Right now, don't know what configuration the motor is. I read VST, but being a 96 it would probably have cool fuel

When the canister filter was removed, was the filter full of gas or was it low?

Canister was half full? didnt pay attention. L315584. And you are correct, after further digging, I have cool fuel. Ordered the following just to have them on site for tomorrow when I dig into this: Fuel filter, Fuel pump, fuel regulator. I figure I can clean out the screen under the regulator if needed. Ill know more when I can test pressure.

So plan of attack is try to start it when cold just to see if its a heat soak issue, cant hurt. Check fuel pressure with a gauge. Swap out the IAC and TPS since they are easy to get to and swap. If no bueno, pull the cool fuel system and install the new parts. Then cross fingers. If no go after that, Ill call a pro as I dont have the time to tinker with it. Wife is on my case to have it running for the Christmas parade as she has been looking forward to it for months (its our first at the new house on the water).

Eddienel 12-13-2020 12:54 PM

Good luck and keep us posted.

AllDodge 12-13-2020 02:56 PM

Check the fuel tank antisiphon valve. It can clog or stick. Its a cheap part but if it sticks the pump will have trouble pulling fuel. The rubber fuel line connects to it iin the tank


https://cimg0.ibsrv.net/gimg/www.off...b6ccdfcb40.png

lear60man 12-13-2020 08:07 PM


Originally Posted by AllDodge (Post 4769110)
Check the fuel tank antisiphon valve. It can clog or stick. Its a cheap part but if it sticks the pump will have trouble pulling fuel. The rubber fuel line connects to it iin the tank


https://cimg0.ibsrv.net/gimg/www.off...b6ccdfcb40.png

I have three valves coming off of the gas tank that feed Port eng, Stbd eng and Genset. Ill swap the fuel line from Port to Stbd. I assume that is what you are referring to? They all have quarter turn valves to shut them off. thanks for the diagram BTW....this guy needs picture books.

lear60man 12-14-2020 01:00 PM

AllDodge, swapped the lines Port to Stbd and no fuel. That was a good guess. Right after that it started pouring rain so delay of game.

Solved! Bad fuel sender. It stuck on 1/4 gauge. Blind luck that we got home on 1 engine.

tgorbett 12-15-2020 08:38 PM

So ran out of gas. Yep that would do it. lol


lear60man 12-16-2020 12:39 PM

The worst part was the wife saying, 'Did we run out of gas'. To which I replied, 'Of course not....the other motor is still running fine'. Which it did for another 30 minutes at idle to get us back home to our lift.

And yes.....I did fess up and tell her it was a clogged flux capacitor.

SB 12-16-2020 12:58 PM

Lol.

Eddienel 12-16-2020 01:14 PM

Now that’s some funny sh t! At least you figured it out and it didn’t cost you a lot of money so all good! Oh those damn flux capacitors!

F-2 Speedy 12-16-2020 02:06 PM


Originally Posted by lear60man (Post 4769407)
The worst part was the wife saying, 'Did we run out of gas'. To which I replied, 'Of course not....the other motor is still running fine'. Which it did for another 30 minutes at idle to get us back home to our lift.

And yes.....I did fess up and tell her it was a clogged flux capacitor.

I took a ride on the Harley about 3 weeks ago, went to put some Staybil in the tank for winter storage, popped the cap and the tank was empty , still showed 1/4 tank on the gauge, how I mad it home have no idea

Eddienel 12-16-2020 02:16 PM

The gage on my Roadglide is dead on but I always go by miles. I had an old shovelhead that would lie to you.

lear60man 12-17-2020 12:42 AM

Discovered there is a company that will deliver Rec90 for about 30 cents cheaper than the local Marina. Got a knock at the door this morning and they were hooked up asking for a fuel load! Filled up the water separator and fuel filter with gas and presto blamo....we have engine noise.

Flushed the **** out of it, three rounds of Salt Away. More Christmas lights to b put up tomorrow and Friday.......Its for the children.

http://i.imgur.com/D0tdxtDl.jpg

KISS....keep it simple stupid. Gotta remember that.

SpidRacer 12-17-2020 07:02 AM

Glad you are back on the water! I just went though a similar experience. 3-hr idle from Sanibel Bridge into the night while also discovering Nav/Anchor lights were also obviously being affected by the Flux Capacitor issues. I made it back ad on to the lift. The Capacitor finally quit when I started to flush. Divine Universe had me covered getting back... Direct replacement Wema-Kus sender now on the way from FMT.

Would you share the fuel delivery source? Thanks in advance.

PS: I'll be watching at the Parade

lear60man 12-21-2020 01:37 AM


Originally Posted by SpidRacer (Post 4769468)
Glad you are back on the water! I just went though a similar experience. 3-hr idle from Sanibel Bridge into the night while also discovering Nav/Anchor lights were also obviously being affected by the Flux Capacitor issues. I made it back ad on to the lift. The Capacitor finally quit when I started to flush. Divine Universe had me covered getting back... Direct replacement Wema-Kus sender now on the way from FMT.

Would you share the fuel delivery source? Thanks in advance.

PS: I'll be watching at the Parade

Here ya go...Palmdale oil. They are out of Ft Myers. Punta Gorda delivery is on Wednesdays. New sender should be here in a few days. Hooking up an inverter to power the lights until we take them off Jan1st. I bought another jug of Salt away because it sat with salt water in it for two days and Im paranoid. Left riser is 130 and the right riser is 109. I also

https://www.palmdaleoil.com/

Pic that was taken from a spectator on the parade route:
http://i.imgur.com/DLodcDXl.jpg

Crude Intentions 12-21-2020 06:57 PM

Just a heads up you can buy 5 gallon jugs of salt away on eBay. That’s what I use and keep a gallon jug full for flushing. Easier and cheaper than always running out.

AllDodge 12-21-2020 07:04 PM

Maybe just get sulfamic acid and make your own salt away

tgorbett 12-22-2020 09:54 PM


Originally Posted by lear60man (Post 4769901)
Here ya go...Palmdale oil. They are out of Ft Myers. Punta Gorda delivery is on Wednesdays. New sender should be here in a few days. Hooking up an inverter to power the lights until we take them off Jan1st. I bought another jug of Salt away because it sat with salt water in it for two days and Im paranoid. Left riser is 130 and the right riser is 109. I also

https://www.palmdaleoil.com/

Pic that was taken from a spectator on the parade route:
http://i.imgur.com/DLodcDXl.jpg

Are you saying this company came to your slip and delivered fuel right to your tank for 0.30 cents less than marina? I have a cousin in Cape Coral with 2 boats on a lift. He may be interested in knowing this.
‘Thanks.

lear60man 12-22-2020 11:43 PM


Originally Posted by tgorbett (Post 4770143)
Are you saying this company came to your slip and delivered fuel right to your tank for 0.30 cents less than marina? I have a cousin in Cape Coral with 2 boats on a lift. He may be interested in knowing this.
‘Thanks.

My boat is on a lift behind my house...but yea. Just got a copy of the invoice via email......$3.16/gal delivered including all taxes. Burnt Store is $3.39 and Fishermans Village is $3.16 (prices 12/22/20). So I have to walk the 'deep discount' back a bit as i was comparing it to what it was before Thanksgiving (3.30 at Fisherman's village). But still, how nice is it to make a call and they fill your boat up without you having to get out of bed?

I put the new sender in today. I ordered it one inch shorter than the old one for obvious reasons hahaha.


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