240EFI Challenger 2000 '01 engine issues after rebuild

[deNick]

Hello!

Got some issues with my challenger 2000 (240efi) after rebuild engine was installed. (rebuild after been heated and broken two lower pistons, stbrd and port)

The engine starts and idles pretty good, runs smoothly up to 2000 rpm. At 2500 rpm - engine rattles, jerks and loses power, loses 100-300 rpm and, if throttle at the same position- stops. If throttle been quickly set to minimum- goes to idle.
Short and quick throttle burst - engine goes to 3500...4000 rpm with a lots of power, but after less than few seconds- stops.

May be lack of fuel injected? Low fuel pressure?

Ало, Бэн, это Данила. ай нид хелп

Please, help


PS How do you think, should I also make oil injection bypass?

 

[Dr Honda]

Thanks for making your own thread. With the new info... it's easy.

In the helm of the boat... there is a little black box, and it's called the "Mercury Throttle Guardian." It keeps your engine from going over 2500 RPM while in neutral, and reverse.

So....

1) Either the switch in the directional handle has gone bad

2) you are trying to rev the engine up, and your don't have it in forward. (it happens when checking things on the trailer)

3) the throttle guardian has gone bad.


Personally... I would just disconnect it. That's the fastest way to solve the issue. (and I did on my boat) besides... sometimes you need more than 2500 RPM in reverse.

As I recall... there was a black/yellow wire, that grounds the ignition. If you lift that out of the key, or the lanyard... it will disable it.


As a final FYI... the Throttle Guardian isn't on any of the wiring diagrams. (lol) I guess they didn't what us to know about it.

 

[deNick]

Thanks a lot, Dr Honda, I will definitely check it, but I don't think that "throttle guardian" may cause this problem because it seems that it works good- because my engine starts only in "neutral" position. At "forward" - no reaction when I turn the switch "on". Or this is another "guardian" ?

 

[Dr Honda]

It's a secondary system, that was installed. (that's why it's not on the wiring diagrams) It's simply an RPM limiter for neutral and reverse. AND... they are known to fail.

I bet, if you asked the guys that hang around here... the majority have disconnected it.

 

[deNick]

Can't find this wire. It should be on the engine (near ignition wires) or near the steering wheel and key switch?

 

[Dr Honda]

Up in the helm, where the steering wheel and key is. You will find a small black box... that's it.

 

[deNick]

tried to find something that looks like black/yellow wire, that grounds the ignition, but have seen nothing even close to it

disconnected several sensors, including TPS. The engine begun work well, ... a little time. After few pretty good launchs,- stops and can not re-start. after TPS been connected- starts well, but with similar symptoms- no power, 2500 rpm maximum.

BTW, it seems that i have no RPM limiter for reverse and neutral- when it works (with TPS disconnected and connected again)- it works over 2500 in reverse and even neutral...lifting by water flow reverse shell

Any ideas?

maybe something must be re-calibrated after engine reinstallation?

PS any ideas how to connect to EFI and check errors without special Digital Diagnostic Terminal? Or where can i get one? Our service shop has only DDT for rotax engines.

 

[Dr Honda]

You need some kind of scanner for the Merc EFI if you want to read the errors. Nothing automotive will work. But... that system isn't a seadoo system... so if you have a local boat shop, that deals with Mercury engines... you could go there to have them check it.


As far as needing to be re-calibrated... it can't hurt... but it shouldn't need to be done.


But... from what you are saying... it sounds like the TPS is in bad shape. When the go bad... the engine will normally just run poorly. I don't think I've ever heard that it won't rev past 2500 RPM.

You can check the TPS with a standard meter. Make sure the resistance changes, without going open, or jumping around.

 

[deNick]

Problem solved.
Spark plugs was bad. Installed new spark plugs,- and voila- no excessive smoke when idle and 6000 without any problem

Burned about 80 liters of fuel (with additional 100:1 oil premixed)- pretty good start and power. Reverse to 5000, but with cavitation (reverse shell causing issuficient water flow).


Will try to find merc efi DDT, anyway.

I'm happy Boat season is now opened

 

[sydneygriffith]

Problem solved.
Spark plugs was bad. Installed new spark plugs,- and voila- no excessive smoke when idle and 6000 without any problem

You must be kidding. lol