Optimax 200 random fuel starvation

**Tuneboy** · 09-10-2023, 12:15 PM

Hello,
yesterday i encountered a pretty random fuel starvation.

Two days prior, i started the engine without using the hand pump as i mostly do (it takes then 3 trys mostly after it will run fine in idle). IF i pump, it takes 2 or 3 pumps to have the pump ball pressurized. And drove like 2 hours with full throttle and cruising. All fine.
Then yesterday i also started it without the hand pump, it took 2,3 trys: fires and then dies after a second. Thrid try and it runs fine. Mind you after the engine is warmed up it is starting first try always.
I drove again for liek an hour, with full throttle and cruising: mixed loads. All good.
Then i was using a flood gate. After the door opened, the engine started as usual and i drove out of it at speed close to idle. And then all of the sudden the engine died because of fuel starvation (sounded like it) and i couldnt started it. Was a scary moment because i had like 15 ships come around me since i was still in the exit of the flood gate!! I jumped back and used the hand pump. I noticed that i took like 10 pumps to get the pump ball pressured.
But after that it started immediately and it was all good for the day (= 6h of driving).

Now im thinking what the completely loss of pressure caused. I dont think that this stuff can just "happen", it must have been a reason.

Its my first boat and i own it for like only 2 month so i dont have any experiance with it yet. I used to repair my cars but with the optimax beeing quite special its a different thing. I was thinking fuelpump but then why would it fail just one time and also during the engine running?

**David - WI** · 09-10-2023, 12:48 PM

You might have something in fuel tank that blocked the pickup tube or a vacuum leak between the tank pickup and the primer bulb? (If it sucks air it isn't sucking fuel from the tank?)

**Tuneboy** · 09-10-2023, 02:55 PM

HI,
could be! But then why would it only occur once?

**David - WI** · 09-10-2023, 03:05 PM

Originally Posted by Tuneboy

HI,
could be! But then why would it only occur once?

If there's something in the tank then it's just random... when it contacts the fuel pickup it gets sucked onto it and blocks the fuel flow.

If it's a vacuum leak it might only leak when the hose/fitting is bent a certain way. So, maybe trimmed up or turned far to the left the hose bends a certain way and the fitting (or hose) leaks more air?

It could be the check valves in the primer bulb either are shot or had something stuck that let the fuel hose drain back into the tank?

**Tuneboy** · 09-14-2023, 06:17 AM

Originally Posted by David - WI

If there's something in the tank then it's just random... when it contacts the fuel pickup it gets sucked onto it and blocks the fuel flow.

If it's a vacuum leak it might only leak when the hose/fitting is bent a certain way. So, maybe trimmed up or turned far to the left the hose bends a certain way and the fitting (or hose) leaks more air?

It could be the check valves in the primer bulb either are shot or had something stuck that let the fuel hose drain back into the tank?

Checking the tank is alot of work, my boat is a 18ft Phantom with the tank burried at the front. But it needs to be done i guess. Ill check the primer bulb first, since this is a quick check.

Nevertheless you think its most likely something outside of the motor? I read that the 2001 mercs have a diaphragm pump which is a maintenance part and could cause my issue. Is this true? If so: Should i change it just to be sure (since its also a maintenance part)?

Thanks!

**David - WI** · 09-14-2023, 10:32 AM

You can get a usb camera for your phone with a light on the end for about $12 to check the tank through the filler?

Yes, I guess the fuel pump would be the easy thing to try first, I didn't think they would start working again if they went bad, but I don't know.

**NICE PAIR** · 09-15-2023, 09:47 AM

I'd look @ the primer bulb as suspect, they have check valves that may be letting fuel leak back when motor is off, they also like to be installed in a vertical fashion (outlet facing up.)

**Tuneboy** · 09-15-2023, 02:33 PM

Originally Posted by NICE PAIR

I'd look @ the primer bulb as suspect, they have check valves that may be letting fuel leak back when motor is off, they also like to be installed in a vertical fashion (outlet facing up.)

Thansk ill check it, might be the most easiest. At my boat its horizontal-ish hanging in the line. If it should be dead straight then that might be also the reason.
thanks

**NICE PAIR** · 09-15-2023, 02:41 PM

Just do the best you can to make it up hill to the outlet that way the weight of the fuel will help hold the check valves shut instead of the other way. Good Luck.

**sonicss33** · 09-15-2023, 03:44 PM

Everything above are good places to investigate. Also, you might want to change this fuel filter and when you have the filter out look down inside the housing for any signs of fuel that has “gelled” due to ethanol. I found this in mine one time, cleaned out the crap and has been good ever since.