merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

[BF]

Hi, I'm through the break in period for my 25 merc 4 stroke EFI.... One annoying thing is that the idle seems to surge a bit within a second after shifting gears. The bump up in idle makes it difficult to shift gears again until it drops back down to normal idle (after 2 or 3 seconds). Doesn't sound like much of a problem, but it makes it nearly impossible to quickly bump it in and out of gear for fine boat control for docking or working around a snagged line.

It seems (?) like the idle control senses a drop in rpm's when going from N into gear, and over-compensates by bumping the idle up. Not knowing how idle is controlled in these thingys, is that about right? I guess there's no way to adjust (lower) idle rpm's?? Aside from the shifting, I wouldn't mind being able to troll slower than I am able to now.

anyone else seen this?

Thx

 

[BF]

Re: merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

^^^

 

[just_crsn]

Re: merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

Hey BF, its does the samething with my motor! It is annoying when you need to shift from one gear to another in a hurry. I also asked the dealer about this to see if there is a fix. But they dont seem to really want to take the time on my LITTLE motor. Im sure if I had purchased a 200hp, i would have recieved better customer service. I also asked them if the could contact Mercury to see if they have any recommendations. I havent heard anything yet......may never. How did you make out on your prop sizing??

 

[BF]

Re: merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

Hey Just.... good to hear from you again. Sorry to be slow responding, we were at the lake. As for the prop, I'm happy with it. I think I made a good guess. I still never rigged a temporary tach, but with me alone and an empty boat, it'll hit 35 mph (according to the wheel speedo on my fishfinder). With a normal load in the boat (a couple adults, or me and a few kids) it'll be just over 32 mph at WOT. Even with an empty boat, I haven't ever hit the rev limiter at WOT, so I don't think I'm under-propped. If I recall correctly, you're running a 12 1/2" pitch.... I have an 11".

I brought my rig home this weekend because some parts fell off the motor. The tiller friction adjustment works by squeezing a stainless plate between 2 plastic pucks. Well the 2 screws and and the funny bushings that hold that curved plate fell off. You might want to check that those bolts are not working loose on yours. Right now mine has no friction on the tiller! It's annoying to run it that way... hard to fish and always have a hand for the motor!

I will mention the surging business to the dealer when I take mine in, but I already expect them to blow it off. When describing it, it doesn't sound like a big deal, but as you know, it sure makes slow boat control a huge PITA.

Are you happy with how slow yours trolls down? I wish mine trolled a little slower. It makes it inconvenient for crawling around the shore and casting for smallies. Especially since the bumping in and out of gear thing is not smooth. Makes me think I should try a small electric trolling motor.

Anyway, that's the update.

 

[BF]

Re: merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

spoke to service dept just now... they're ordering the parts that fell off. I mentioned about the surging idle. Service guy said others had complained about that, and that he'd talk to the tech as to whether there are any updates to address it. As far as he knew, they did not have the capability to flash upgrades to the chip on these motors. He said they occasionally do flash upgrades on the larger EFI's to address issues like this.

I'll post what ends up happening (or not happening).

 

[just_crsn]

Re: merc / tohatsu 25 hp 4 stroke EFI - surging idle ?

Wow BF, that boat is smokin fast!! I may have to try tweaking to see if I can get a little more speed. Thanks for the heads up about the co pilot problem. I did check mine....everything seems good but I will keep a eye on it.
Your right about it being a nice feature on the motor.....I run mine with tension on it all the time......i dont like the feel or control without it. I also have been doing alot of boating and fishing this year.......just got back from a few days off. Hotter than the sun here lately!!! As far as the trolling speed ......i agree ,would like to see it run a little slower. I do have a foot control trolling motor on my boat......I would strongly recommend one. They are great accessory to have. A little pricey but I would buy another one if something happen to this one. Really nice to be able to fish at the sametime moving the boat in and around those fishing holes.