200 Optimax Overheating Fuel Starvation ?

[jeffs7599]

Really need some help on this. I have a 2002 Utopia 185 with a 200 Optimax engine. I cannot find a local mechanic that will even touch it. To make matters worse, Im deployed overseas with the Marines. So I cant even work on it again until I get back. Im really looking forward to using it this summer. I get home in April, which gives me a few weeks to get it working before summer vacation. I work at Homestead AFB in south florida, and really want to use it in Florida this summer.

Problem: engine runs and starts fine, after 15 minutes the starboard side cylinder head overheats and the engine shuts down. No beeps or horns. After the engine cools off for about 30 minutes it will start right up. Ive check the cooling and air pressure system, and both seem fine. My neighbor is a boat mechanic and suspects the fuel pump. I didnt have time to mess with it before I deployed. I spent the whole summer trying everthing I could think of cooling wise, but didnt spend much effort on the fuel system. Im ready to just buy a new fuel pump and filters. I meant to try a car pump and run it from an portable tank, but just didnt have time before I left and put the boat away in storage. All covered up.

Help: what fuel pump do I need and where should I buy it. Ive attached a photo of the serial number and one of the fuel pump. The pump does run when i apply power, but I did not check pressure. Cant find the part number off it. Just says SAE J1171 which of course means nothing.

I did find this on ebay: Fuel Pump Assembly Mercury DFI Jetboat 885555T03 for $187.

Questions:

1. can the full or partial failure of this pump cause the above symptons (overheating and stalling out)
2. Should I get this pump, or maybe go with a generic aftermarket?


Fuel pump says

 

[Dr Honda]

Welcome, and thanks for your service.


OK.... since this is just the first swing at things... let's just jump in.

1) Why do you think the fuel pump is bad?

The Opti engines are direct injection, and need a lot of pressure to get fuel into the cyl's. If it's supplying enough fuel to keep one side of the engine happy... the other side should have enough too. Sure... there could be a blockage, and dropping pressure to one side, but in all my years, I'm NEVER seen that happen.

2) The pump in the picture you posted is just a lift pump. It brings fuel to the vapor separator. If it was bad, it wouldn't start.

The high pressure pump is in the vapor tank, and that one could be intermittent, or wearing out. BUT, to know... just put a pressure gauge on the injector feed line. You are looking for 90 psi. If it's low... it's bad. BUT, that doesn't explain one side being starved.

3) How do you know the starboard side is overheating? How have you checked it?

OK... if it is overheating... it could just be plugged with sediment... or if the last owner put thermostats in it... the one in that head could be stuck. There's a water fitting at the top of each head, and a hose comes out of it. Take the 2 bolts out, and look inside. If you find a thermostat... chuck it in the trash. (Then take the one out of the other side) They run better if you keep the engine temp steady... but in Florida... they aren't needed. HECK... I don't even run them in PA, and it can get chilly before I put my boat away.

To answer your questions....

1) Yes, but not the way you are describing.
2) I wouldn't until you actually check the system. Otherwise you are just throwing $$$ down the drain.


Once you are home, and we can actually test/check a few things, we will move forward faster.

 

[Dr Honda]

one last thing....

generally, if a 2-stroke is running lean enough to overheat... you will melt pistons. So... if it's happened more than once... you would have a dead engine. Kind of tells me something else is wrong, but we will get you fixed up.

 

[jeffs7599]

Dr Honda. Thank you for the detailed reply. I apologize for not responding sooner. Im still in the desert, and have limited access to a computer, and no access to my boat.

To answer your questions... Ive used a laser thermometer on both cylinder heads. It has all been very baffling. Ive done just about everything I can research regarding water flow/cooling. That seems ok. Ive checked and it does not have thermostats. Ive removed the coolant lines and passed water through manually to check for blockage and all seems fine. Basically, Im trying to explore if its possible to be fuel related, since Ive done everything I can do regarding water and cooling.

Whats odd is that it starts and runs fine. It can idle and do fine. Whats odd is that it stalls. No horns or beeps. Conks out if I try to run it at anything above idle for more then 15 minutes. I pop the cowling and hit it with the laser. Starboard is head is very hot. I forgot the temperature. Port side is about 150 degrees.

My neighbor is a PWC mechanic and has looked it over briefly. He thinks I may have spent too much time chasing down cooling and should like into the fuel system. Working in aviation, Ive seen fuel as part of some cooling systems.

At this point Im just short on time and patience. I was supposed to be home by now, and Im not. So that means I have about 2 weeks in May to get this working. We have our annual trip to Orlando in early June to take all the kids on the lake. Im willing to spend some money up front to know its going to work. But I cant put this off. So hard to find a mechanic to work on these, that actually know what they are doing. I had one mechanic in Texas hold it for 2 months, before he gave it back and said he didnt know what was wrong. DIdnt charge me, but wasted my time.

Time isnt on my side here. Just tired, and ready to get home and see water. So Im willing to buy the fuel pump assembly if it will save me time, and if its a possible culprit if the cooling system can be ruled out.

 

[noviceskier]

Dr Honda. Thank you for the detailed reply. I apologize for not responding sooner. Im still in the desert, and have limited access to a computer, and no access to my boat.

To answer your questions... Ive used a laser thermometer on both cylinder heads. It has all been very baffling. Ive done just about everything I can research regarding water flow/cooling. That seems ok. Ive checked and it does not have thermostats. Ive removed the coolant lines and passed water through manually to check for blockage and all seems fine. Basically, Im trying to explore if its possible to be fuel related, since Ive done everything I can do regarding water and cooling.

Whats odd is that it starts and runs fine. It can idle and do fine. Whats odd is that it stalls. No horns or beeps. Conks out if I try to run it at anything above idle for more then 15 minutes. I pop the cowling and hit it with the laser. Starboard is head is very hot. I forgot the temperature. Port side is about 150 degrees.

My neighbor is a PWC mechanic and has looked it over briefly. He thinks I may have spent too much time chasing down cooling and should like into the fuel system. Working in aviation, Ive seen fuel as part of some cooling systems.

At this point Im just short on time and patience. I was supposed to be home by now, and Im not. So that means I have about 2 weeks in May to get this working. We have our annual trip to Orlando in early June to take all the kids on the lake. Im willing to spend some money up front to know its going to work. But I cant put this off. So hard to find a mechanic to work on these, that actually know what they are doing. I had one mechanic in Texas hold it for 2 months, before he gave it back and said he didnt know what was wrong. DIdnt charge me, but wasted my time.

Time isnt on my side here. Just tired, and ready to get home and see water. So Im willing to buy the fuel pump assembly if it will save me time, and if its a possible culprit if the cooling system can be ruled out.

Just a wild guess and no clue what I'm saying but is there a small chance it could be exhaust related?