Priming fuel system for new engine first start.

[500dollar744ti]

I installed a new engine in my boat. Was a 350 magnum, new engine a carb'd 6.2 scorpion. The fuel system has been apart and I'm not sure if there's anything special needed to get a prime after everything has been apart. I smoked the old starter with too much cranking trying to get fuel to the carb. How long should it normally take to fill the fuel water separator on a first start like this? Before I smoked the starter, it did run shortly on carb cleaner, it has spark. Trying to get a prime to the carb so I can get 'er running and set base timing.

Any special way to get the fuel system primed before I start cranking on the replacement starter?

 

[Alumarine]

I would fill the filter with fuel and pour a few ounces of fuel down the carb.
And keep cranking down to 15 seconds with a break between tries.

 

[Scott Danforth]

When cranking. 15 second on, rest for 1 minute

Prefill the filter

 

[Scott06]

has the engine been run on a stand first? When i ran mine on a pallet i took the plugs out cranked it on starter until it showed oil pressure , by then it was primed fuel wise. Dump a little gas down the carb it will run long enough to prime the fuel system in the boat

 

[ROY WILLIAMS]

I cranked the engine 5 sec ... then I put one ounce in the carb. also put the water container filter the gasoline .. then crank it 5 sec .. then 2 -3 min then crank again ... crank the throttle then crank again ..
you cranked over 15 seconds then a lot of cranking .. hot as hell ..

 

[500dollar744ti]

I have a little primer bulb like the kind you would use on a small outboard gas tank. Thinking maybe I could save myself some trouble by hooking it up before the mechanical fuel pump and just pumping it up until there's gas in the filter/separator and I can see the jets spraying in the carb. I dont want to roach another starter. The starters already get stressed turning the water pump impeller in addition to the normal rotating assembly.

I'd think that would work. Hell I could just leave it on there for the future after I start first time for the season.

Thoughts on using outboard primer bulb in line from tank to engine to get it primed?

 

[Scott Danforth]

I cranked the engine 5 sec ... then I put one ounce in the carb. also put the water container filter the gasoline .. then crank it 5 sec .. then 2 -3 min then crank again ... crank the throttle then crank again ..
you cranked over 15 seconds then a lot of cranking .. hot as hell ..

Assuming mechanical pump......Did you forget the fuel pump push rod?

 

[dubs283]

Thoughts on using outboard primer bulb in line from tank to engine to get it primed?

Not recommended, no inboard engine has a primer bulb anywhere in the fuel system. No reason to add one, it'll just cause a restriction that will cause other issues.

You need to troubleshoot the entire system from tank to carburetor, adding a primer bulb is masking the real issue

If you add fuel directly to the carburetor does the engine run?

 

[500dollar744ti]

Assuming mechanical pump......Did you forget the fuel pump push rod?

I did NOT forget it! Made very sure to install but definitely appreciate the thought because if I did forget that would be a big problem

 

[500dollar744ti]

Not recommended, no inboard engine has a primer bulb anywhere in the fuel system. No reason to add one, it'll just cause a restriction that will cause other issues.

You need to troubleshoot the entire system from tank to carburetor, adding a primer bulb is masking the real issue

If you add fuel directly to the carburetor does the engine run?

The engine runs on carb cleaner, did not try pouring gas in. The filter separator is probably empty. I was talking about adding the primer temporarily to fill the whole system with fuel up to the carb bowl. If its a restriction I can take it out after. If I pour gas in ill have to reinstall the flame arrestor each time because the timing isn't set yet and I don't want a backfire explosion. The whole fuel system was empty. I thought it was going to be like my old Ford truck where after sitting for months it takes some cranking but the pump eventually fills the system. Only difference is I dont have a giant water separator that has to fill with gas before it gets to the carb. I'm just exploring ways to get the whole fuel system primed that won't involve excessive cranking. Once its primed, I shouldn't have an issue. Just never dealt with this on a boat with the water separator and wasn't sure if there was some official procedure.

 

[dubs283]

There's no official procedure. It shouldn't take long for the mechanical pump to prime the system even when completely dry if everything in the system is sound.

Burning up a starter means you had a weak starter, there's an issue with your fuel supply system or possibly both

Priming your carburetor with carb cleaner makes no sense, first off it does not burn well and the engine is designed to run on gasoline. Use gasoline to prime the carburetor and if reinstalling the flame arrestor seems too much a task for you then this entire scenario may be beyond your scope

 

[500dollar744ti]

The engine runs on carb cleaner, did not try pouring gas in. The filter separator is probably empty. I was talking about adding the primer temporarily to fill the whole system with fuel up to the carb bowl. If its a restriction I can take it out after. If I pour gas in ill have to reinstall the flame arrestor each time because the timing isn't set yet and I don't want a backfire explosion. The whole fuel system was empty. I thought it was going to be like my old Ford truck where after sitting for months it takes some cranking but the pump eventually fills the system. Only difference is I dont have a giant water separator that has to fill with gas before it gets to the carb. I'm just exploring ways to get the whole fuel system primed that won't involve excessive cranking. Once its primed, I shouldn't have an issue. Just never dealt with this on a boat with the water separator and wasn't sure if there was some official procedure.

I'll try pouring in some gas this afternoon once I replace the starter. I'm not inept, I built the engine in my garage, I am just a bit younger and didn't grow up with carburetors. I don't have the just pour an ounce of gas in the carb techniques because I didn't grow up with that. Still open to learning stuff. Thats why I asked on here.

 

[Bondo]

Only difference is I dont have a giant water separator that has to fill with gas before it gets to the carb.

Ayuh,..... Pre-fill it, before ya screw it onto the housing,.....

Does yer tank, freely give up it's load,..??

 

[Eric 3.7LX Alpha 1]

I have a little primer bulb like the kind you would use on a small outboard gas tank. Thinking maybe I could save myself some trouble by hooking it up before the mechanical fuel pump and just pumping it up until there's gas in the filter/separator and I can see the jets spraying in the carb. I dont want to roach another starter. The starters already get stressed turning the water pump impeller in addition to the normal rotating assembly.

I'd think that would work. Hell I could just leave it on there for the future after I start first time for the season.

Thoughts on using outboard primer bulb in line from tank to engine to get it primed?

It would work, and then engine would run fine with it inline, but they are not allowed in an enclosed engine compartment.

 

[500dollar744ti]

WELL! I fault traced the fuel system. I got fuel in the separator, plenty of fuel going to the pump, crack the pressure line at the pump and it has pressure... but nothing at the carb. I've been an auto mechanic for 20 years and never seen anything like a plugged up metal fuel line after a filter but here it is. Had to break it up with a drill bit then blow it all out with compressed air. Maybe mud dobbers? The line was exposed outdoors while I was working on the new engine. Looks like it was packed full of rock hard dirt.

 

[Scott Danforth]

Had mud daubers fill every drilled hole in my interior.

 

[500dollar744ti]

Had mud daubers fill every drilled hole in my interior.

Nothing has really gone smoothly on this. First the mud daubers in the fuel line. Then I start it and the guage reads 0 oil pressure. I know that's wrong because I primed it and tested the pressure switch. I pulled the oil pressure sender and found a piece of thread sealant blocked the hole. Cleaned that out, gauge shows good oil pressure.

Then I noticed a slight knock that sounds like rod knock. It's gotta be that stupid oil pan baffle I swapped in from the old motor. The stroker crank was hitting it so I clearanced the baffle plate but I guess it is still touching somehow. I'm not taking that motor apart again so that thing can self clearance now for all I care.

This picture was where it was touching the baffle plate. I beat the baffle plate with a hammer to make clearance but I suppose I didn't do a good enough job. That was the only thing I was worried about on this motor. Oh well.

 

[Scott Danforth]

use a hammer and dimple the windage tray where the crank throws are

 

[500dollar744ti]

use a hammer and dimple the windage tray where the crank throws are

That's what I did. That has to be where the knocking noise is coming from still somehow. I'm going to run it some more and see if it quiets down.

 

[500dollar744ti]

use a hammer and dimple the windage tray where the crank throws are

One more question since I know you'll have this memorized, on Thunderbolt IV ignition, setting base timing is just setting the timing at idle speed right? There's no wire to ground or anything to turn off advance curve, you just set it as it sits correct?