98 Ficht- misfire - injector or plug wire

fichtfart

Cadet
Joined
Sep 23, 2002
Messages
16
I have a 1998 Ficht 150- and yes I?m aware of its history, I got it new in 03/98.
I?ve got the updates and have pampered it for 13 years- still fires up on the 1st cylinder up and ?.(don?t want to jinx myself)- I?m happy its lasted this long-
A couple of nuisance topics though-
1) If you?re not supposed to put shims on the spark plugs to index them- without buying a couple of hundred- how can you get them in the index range of the pinned head? I swear I?ve got about 15 plugs that were all threaded identical- and all land 180deg from the pin. Do you keep buying plugs till they fit? Why not shim?
2) The past 2 or 3 years I?ve had a little hesitation in idle and low RPM- perhaps a misfire is a better word. The engine starts great- and runs fine- but there is an intermittent, non-cyclical misfire that increases frequency somewhat from 1k-2k into 3k and 4k. Above 4k I think it just gets drowned out in the high RPM range. I have no loss or RPM, and the power seems to be ok. The motor doesn?t run ?rough?, but you can feel and see a bit of vibration in the boat. If I were to compare the ?feel? of it- think of an old farm tractor in idle- how it has a rhythm- and just once in a while an extra ?pop?.
-But- a couple of outings ago- after taking a WOT lap or 2, then shutting down to beach- when I took off again there it seemed to be so rough at high rpm, 4k and above, that the motor had no guts (from a whole shot). I shut off the engine- pulled the hood- checked wires (?)- Started it up again- and it seemed to be ok for the rest of the outing (slight misfire was still present though). Since then I can tell that some ?dynamic? has changed at WOT- I still can jump on it from 1k to 55k and have power out of the hole and maintain the rpm- but I may be feeling that misfire at the top end now. (funny thing is the last 2 or 3 years the dash tack can get into 6200rpm if I let it-( I thought 5600 was top end)- ( I keep it to 5400)
Anyway- I?ve long suspected a fuel injector since I had it in for repair years ago and the mech touched and possibly rotated the screen- but I?ve also suspected the plug wires because some don?t ?pop? on the plug like they should. I replaced a wire tonight because it would grip the plug- and actually pushed itself off the plug (air pressure in the boot). Its spring clip was broken ? I don?t like ?making? plug wires, but that?s all the local dealer had. Something else ? the plug wire I took off had a busted spring clip on it- but the cable resistance was 21k ohms. What?s up with that?? The one I made and put in was 2ohms. I also found 2 plugs (1 with a shim and the one with suspect plug wire) both had a lot of carbon on them.
After the new wire- out for a ride. Started right up- WOT out of the hole, throttle up/down/goose it/punch it/ WOT for 5 miles?the misfire is there- ever so slightly, and there is a slight vibration or pulsing harmonic at WOT. But no loss of power or RPM, but you can tell that something?s different
I have the software for diagnostics- would I be correct is assuming that if I can maintain the ?misfire? at 2krpm, and dropping the cylinder it goes away that its either that injector or plug wire? Or should I just replace the plug wires as well (others don?t grip and their resistance is high as well)
I know I?m limping on this motor. Mechanics and parts are huge $$$$ for this engine- and the motto has been- if it starts and runs- ?don?t throw lots of $$$$ in it?, because if it goes in for major repair- it?s coming out a Merc.

thanks
Wayne
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: 98 Ficht- misfire - injector or plug wire

Stay with original plug wires on that engine or you may end up with a crashed EMM!
Give it a decarb with Engine Tuner and try to add Carbon Guard to the fuel.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: 98 Ficht- misfire - injector or plug wire

I'd do a cyl drop test on it and see if you can narrow it down to any one cylinder.
 
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