Flywheel magnets

adamb · 23-05-2010, 05:47 PM

Hi Boatmad

Need some advice.
I have a merc 200hp 2.5L offshore motor which appears to be fitted with an XR2 2.0L power head, the carbs and electrics are stock 200hp 2.5.

4 up with a boat load of gear and half a tank of fuel the boat will pull 54mph (GPA and speedo agree) at 7500RPM with a laser 21 seemingly with out any distress

Boat has allways had a very rough idel and poor holeshot which I have been trying to improve.

Pulled flywheel off and found 5 out of 6 outer magnets broken and loose.

Questions
1. Is this likely to be cause of rough idel and missing?

2. should i replace it with an XR2 flyweel and 18A stator?

Jay Smith · 23-05-2010, 07:08 PM

Could be , its surely not the best thing for your engine and if the magnets become dislodged under power it WILL make a mess of your stator, trigger and the stator perch as well as your wallet.

Sounds more like a reed issue and or a bad idle on carbs this could also be float levels wrong, they can be set too high and flooding of idle circuits. OR the small higher in the carb body idle circuit jet is plugged.Also hopefully you have NOT cross drilled your intake ,that ALWAYS makes for a crappy idle and a bear to tune.

Cheers,
Jay

adamb · 23-05-2010, 08:53 PM

Hi Jay,

Thanks for your reply. I am hunting for a replacement flywheel, get that sorted first. I have it in mind to look at the reeds and the bores if only to confirm what I have got!
I believe the power head is a European class 3C 200hp 2.0L. The date under the throttle arm 2 13 92 and the block flange is stamped 1628 and the block casting number is 884-9765-C. The heads are stamped 26cc and the compressions are 135-150psi WOT but cold.
The reason I am suspicious of the ignition stator fly wheel is that there was debris under the flywheel and the wires coming off the stator and trigger don’t look to good, although basic meter checks were OK. The debris is corroded iron core laminations, there are some quite large bits of magnet missing but no sign of rubbing contact.
I have built a DVA from a diagram I found on Scream and Fly, I haven’t had a chance to try it yet. (What’s happened to S&F tech forum it’s been revamped and only goes back to April, has all the historical information been lost?)
The engine started and idled well cold but then went off (gets rough and misses) once warmed up. Main use is water skiing so idle and holeshot are a priority.