Merc 200 problem?

[cman]

I'm working on a merc 200 efi. It runs great when the weather is cold but it has NO holeshot when the weather is hot and humid. Won't hardley plane out. The guy has replaced the fuel line but didn't help anything. Any body got any suggestions. I can't really see for myself until the weather warms up so I would appreciate any suggestions.
There are no fish in this pond

[rocket]

You might check and see if the prop is slipping in the hub,happened to me once.Also check and see if the vent is ok on the fuel tank.

[rocket]

You might try checking the prop to see if the hub is slipping,happened to me once.Also check the vent on the fuel tank

[CTFSHWHISKER]

It is probably something in the computer not adjusting fuel to compensate for temp change,there is a computer to hook it up on and you can test all the systems,with out doing that it will be hit or miss if you fix it.

[Basswipe]

I'd say the problem is in the ECU. That's the brain box that controls the fuel injection.

There's no fixing an ECU. If somethings wrong, you replace the box. They're outrageously expensive to buy from a dealer. Somewhere along the lines of $1,600-1,800.

I have a 200EFI and mine went bad last year. I found one on the internet for $200. It came with a guarantee to work upon installation. I put it in, and the engine has run perfect ever since.

[FISH2MUCH]

I HAVE A MERC 225 EFI JUST HAD IT FIXED. I HAD PROBLEMS GETTING ON PLANE AND LOADING ON TRAILER BUT ONCE IT GOT ON PLANE IT WOULD TAKE OFF AND GO. MY MECHANIC FOUND A HOLE IN THE PUMP DIAFRAM. . I WOULD REBUILD THAT DIAFRAM PUMP FIRST BEFORE BUYING A COMPUTER. AT LEAST IT WILL BE GOOD MAINTENANCE. I RECOMMEND JUST ADD WATER MARINE ON DIXIE HWY. DAVID 744-4714

[CTFSHWHISKER]

Actually you can get them from rapair,i replaced a few at the school i went to at louisville tech.They can redo yours and you can have them reprogram them or just send yours as a core and they'll send another.It may be an ecu but there are sensors that can cause the same problems.IF you do decide it may be the ecu maybe you know someone who will let you swap and run before you buy one.
If you want to,check out a story in bass and walley they did about the reprogramming of fuel and timing and rev limiter,it picked up the overall performance of a ranger very respectfully,especially in the fuel saving category.

[cman]

My guess would be the air temp sensor is whats bad. I'm not sure how to test it though
There are no fish in this pond

[stoner]

Click the Merc forum link on BassBoatCentral, those guys are pretty good. By the way how old is you're 200?
Stoner:)

[cman]

Its not mine. I'm just working on it. Its a 99 model though. I've posted it on bbc but no replies yet thanks.
There are no fish in this pond

[CTFSHWHISKER]

Most sensors are tested using an ohms meter,you will need to find the base ohms reading then you will need to apply a temp change and note the ohms readings to see if it in spec or not,according to the merc manual,i have one but i am getting ready to put a water pump on my truck i will check the procedure and post it to you later this evening.

[CTFSHWHISKER]

you may get a reply in a month or two,i have asked things before then get a reply months later.