Dont throw out those high dollar High Pressure fuel pumps yet

[flyingfrizzle]

I have been working on a early 2000s 2.5 Mercury 200 efi this week and first thing I did was drained the gas out of the vst and hooked it up to a 6 gal portable tank. Added pre mix to the tank with the oil injection still intact for double oil or a fail safe if the injection was bad. Then I added new impeller plus t-stats. Could not get it to stay running, it started and then cut back off. I checked for fuel pressure at the test valve and nothing. Turned the key on and then click click click from the vst inner fuel pump but no constant buzz. I had a stuck high pressure pump in the vst, It wanted to run but wouldn't. I disassembled the vst and it looked surprisingly clean, which the original owner worked at a marine service center and was a mechanic and took week care of the motor I was told. I do believe this due to the t-stats looked good when removed and other items were up to par but the second owner I bought it from used it few times then it sat for 2 years. I got it cheep with a nice 23' proline walk around hull and trailer fully rigged and it was running fine when parked 2 years ago. Any how I cleaned the vst tank and used throttle body cleaner to remove the little varnish in the bottom of the canister after removing the high pressure pump. I took the hp pump and cleaned it well then got the non removable filter screen off the bottom and added some Lucas fuel treatment in it and let it sit a moment. I read online that some times you can reverse the polarity (swap + & - ) and pulse the pump in reverse on a spare battery with jumper wires going directly to the terminals to break it free so I tried this and click click no run. Went back and forth a few times and no luck. I also read that there were no fixing these pumps and that they just had to be replaced but I was not giving up that easily. I filled the pump up threw the suction hole with throttle body cleaner and shook it for a few minutes, turned it upside down, brown came back out as the cleaner was clear. So I done it again several times and got it to come out some what clear and then tried to break it free again. I did the forward reverse pulse again several times till the clicking turned into 1 second runs to 2 second runs to 3 second runs in forward. I would only pulse it in reverse but hold it on the battery connection jumper in forward. Finally it ran and stayed running! Took a gallon container full of gas and a empty gallon container and used a clear tubing hose over the outlet to transfer gas back and forth between the two tubs to get it flowing and flushed out. I added some treatment to the gas and back and forth again. I jumped the wires at the battery not the pump because of the spark when I removed the wire. You don't want to do it at the pump due to the gas. I used 5 foot cables to get the sparking jumper clip at the battery terminal away from it. The pump ran great and sounded good, The first batch of gas turned light brown after recirculating it for a few minutes but the second stayed clean so I feel like I got all the varnish out of the pump. I don't think it was too bad due to the vst look fair just enough to make it stick in place. Needless to say this saved me $500 for a new aftermarket pump and $700 for a oem pump. I didn't have much hope in the pump but had to give it a try and it worked out. This may not always work but worth a shot it you let you motor set up awhile with out drained the vst tank and fuel rails. I reassembled the system and pumped the ball to fill the vst tank and flipped the key switch on, I could hear the pump running. I let it run for 20 seconds or so then hit the key to start and it fired up instantly and stayed running this time at idle. She smoked like hell with the double oil but I did verify the oil was injecting. I will heat it up tonight to see if the t-stats are working right and let it get some idle time with the double oil to oil everything up well. I got some fuel treatment to add to the tank to run threw it and may runs some sea foam in it as well. The compression was 117, 118, 117, 110, 117, 115 so I think I'm good there. Factory calls for 120 for my motor and heads according to the solco manual. I would like to find a factory Mercury manual due to everyone says they are much better. For the wake up break in I am not sure how to run it but will take it easy for a while and slowly build rpms until she is broke back in. I also changed the plugs, I am going to change the wires due to a boot has some cracks on one. I did the impeller and t-stats, the water separator and also will change the lower unit oil tonight prior to running it up to running temp. What did I miss? What else do I need to do and what is the best way to run it the first time in the water?

[flyingfrizzle]

Picture of the Proline:

[Old'sCool]

I would probably perform a decarb for ring/land carbon removal and then re-check compression.

[flyingfrizzle]

Originally Posted by Old'sCool

I would probably perform a decarb for ring/land carbon removal and then re-check compression.

I plan on running a can of seafoam 16oz with 3/4 gal of gas (100 octane ethanol-free fuel is all I run) threw the motor in 3 - 15 min sessions

I may even get the spray type and tilt the motor up and spray it threw the spark plug holes while rotating by hand and let the rings soak too

[eggsuckindog]

Dude you wore me out with your post and I couldn't finish it - I unfortunately am an expert in 2.5 EFI troubleshooting - you can IM me or just call me me 813 369 3256 - I can prolly tell you exactly why it won't run or what to check

[flyingfrizzle]

Originally Posted by eggsuckindog

Dude you wore me out with your post and I couldn't finish it - I unfortunately am an expert in 2.5 EFI troubleshooting - you can IM me or just call me me 813 369 3256 - I can prolly tell you exactly why it won't run or what to check

Thanks for the offer and I will keep your number if I have any future problems but I got it running just fine now, The high pressure pump was stuck from sitting with old gas in it. I was just posting what I did to un-stick the pump and get it back useable. I know many people who have issues come spring after their motors sat all winter and they have to replace the $700 vst fuel pump. I just was trying to help others that had pump problems save the big $ if they want to try to get their pumps back going vs replacing them.

The 2.5 runs great and I found a second motor as well. The plan is to pull them apart and hop them up a bit. I want to do a 7 pedal front end, high compression heads, some porting in the exhaust chest, porting in the intake, rod slots, lighten the fly wheel, bump the ports up to promax specs, maybe a svs system and a few other special things. I already got burcato acu's so I can adjust the fuel curve and set a higher rev limit. Hope to get 500+ hp out of the pair.

[eggsuckindog]

That pump is available from Bosch for $200 - google Mr Fuel Pump - go over to Scream & Fly there is an excellent engine builder quite close to for all your Mod's

[Bigshrimpin]

Originally Posted by flyingfrizzle

Thanks for the offer and I will keep your number if I have any future problems but I got it running just fine now, The high pressure pump was stuck from sitting with old gas in it. I was just posting what I did to un-stick the pump and get it back useable. I know many people who have issues come spring after their motors sat all winter and they have to replace the $700 vst fuel pump. I just was trying to help others that had pump problems save the big $ if they want to try to get their pumps back going vs replacing them.

The 2.5 runs great and I found a second motor as well. The plan is to pull them apart and hop them up a bit. I want to do a 7 pedal front end, high compression heads, some porting in the exhaust chest, porting in the intake, rod slots, lighten the fly wheel, bump the ports up to promax specs, maybe a svs system and a few other special things. I already got burcato acu's so I can adjust the fuel curve and set a higher rev limit. Hope to get 500+ hp out of the pair.

FF - From what I've read if you stay under 7000rpm then you are better off with the 4 petal front. I just sold a 7 petal 2.5L front 1/2 last week on ebay. I'll keep my eyes out for another one. 2.5L 7 petal fronts are tough to find cause they were only on the 1991/2 2.5 with the bottom guided rods, a 240 sportjet, promax, or racing stuff. Can't wait to see the end result . . . that boat will fly. Thanks for the info on the hi pressure pump. You might want to pull the head on the 110psi side and just take a look. Worst you'll lose is a few bucks for a new head gasket.