8v92's won't start summer commissioning.

[racclarkson@gmail.com]

Air flaps?

Emergency shutdown dampers. FWIW, motors will start and run fine with the dampers closed at low RPM. What bothers me about your issue is that both motors are doing the same thing. The chances of a double failure are pretty low which means you need to look at the lowest common denominator. That's fuel. Double fuel line clogs, double fuel pump failure, double air in fuel lines are all possible, but what are the odds?

You are aware that your Racors have two valves per side, right? A double Racor (one set per motor) has fuel inlet valves (2) on the front side and fuel outlet valves (2) on the backside; that's four valves per motor. Don't know how long you've had your boat, any chance you've overlooked this?

[kelpy]

I have never had a DD able to run at any RPM if the damper doors are closed. They wont even begin to start. That is the whole idea behind them.

If my engines did somehow manage to start or run with the dampers closed, that condition would be rectified immediately. Again, YMMV.

[rustybucket]

Since both engines are affected it's probably something simple/overlooked.

I'd start by checking in this order

1. Air Flaps (emergency shutdown air flaps). I would trigger and reset them a couple times just to ensure proper operation. Remember they have to manually re-set on the engine, you can't just push the T-handle back in.
2. Fuel valves (on my boat 3 fuel valves have to be in the proper position)
3. Shutdown Solenoids (make sure they are in the correct position by having someone press the button while visually inspecting their action)

After those 3 were checked and still no run condition I'd look to prime. If they initially cranked and ran I don't think you have lost prime.

[dsharp]

I’ve wondered what keeps the fuel from siphoning back to the fuel tank and causing the priming issues. I had one engine that I always had to add fuel to the racor if it sat for any length of time. I checked the supply side and never found any type of air leak. Can fuel siphon through the return line?

[SEVEN]

I think that is exactly what’s happened. Boat sits for a long period of time, fuel drains back and air is trapped, the motors won’t start. Get them primed I’m sure they will fire right up. Good luck.

[Pascal]

One easy way to prevent any symphoning back when the boat isn’t used for a while is to shutoff the fuel valves ... simple

[kelpy]

The fuel can't drain back unless there is an air leak.

Worn out, dry rotted 30 - 40 year old fuel hoses will cause such an air leak. I've seen it time and time again on older boats.

[drburke]

I can tell the easiest (and wrong) way and all the experts will chime in as to why this is a terrible way to do it ...give a shot of ether...

I am no expert but would never use ether. Nor WD40 for the same purpose.

These are two-strokes and during the cycle both the intake and exhaust are exposed and can ignite the ether in the airbox.

https://www.youtube.com/watch?v=NgB1dDunbOg

DAN

[drburke]

When my engines were losing prime and hard starting, I also got a brass pump, which did work but was annoying to use.

But I also replaced my old fuel hoses (as was suggested). (BTW, the "high pressure" lines are actually to meet USCG two minute fire burn-through exposure limits not 2000 PSI)

But eventually I replaced my fuel pumps with new ones--cheap and easy job. Much greater suction cured all of my priming issues.

DAN

[dottieshusband]

It's a classic loss of prime issue. If you don't have a priming pump, or hand priming pump, remove the SECONDARY fuel filter, might be a spin on, or canister type. Fill it to the brim with clean diesel fuel. Even though their is fuel in the r a c or s, remove the lids and top them off too. Then crank it for a while. DO NOT CRANK IT WITH DRY FILTERS. It's not good for the fuel pump or injectors. Pressure priming is the way to go, but topping the filters usually works too.