fresh eyes- purring like an angry kitten...

212rowboat

I've kept quiet about this until I figured it out- but the truth is I didn't figure it out... 

My new engine had issues.. the valve train wasn't tuned at all- I got to do some old school adjusting, and swapping of a few components... I expected the engine to run much better after that.  nope.. it trickled off and then flat out wouldn't start... checked everything I could think of.. I was a hair from running a hot lead straight to the coil, thinking something was wrong with the wiring.. it had a new cap, and wires (plugs too), so I couldn't wrap my brain around what was causing my issue.. 

it was SO simple... and something I never would have guessed in a thousand seasons... SO simple... 

a flippin' plug wire was bad... ONE... the guy who came to help has forgot more than I've ever known, and it took him about five minutes to figure it out.  ONE plug wire, which is something I didn't know, will ground against a ground, and because of damaged filament, and the dizzy with spray juice indiscriminately... I never knew that.. I always figured there would be just a dead cylinder... nope... 

I swapped out ONE wire with a new set I purchased, and that engine is PURRING... well, it's blop blop blopping in a way a good engine should, but it lives- the valves are now properly lashed and tuned, and she is DIALED in... the throttle response is incredible.. I set the advance @ 12* as the builder rec'd, but left it loosish and have a gun aboard to do the fine tuning...  after about an hour of straight running on muffs, and varying throttle between 800 and 1800, the rings let loose and the blow by is minimal... the carb required some fine tuning... It'll pull 18" of vacuum at idle, which confuses me quite frankly- I was only expecting about 14 or so.. the needle on the vacuum gauge looks like a textbook for a healthy engine... that is one helpful tool everyone should have.  

I ran off the specs to this guy, and he thinks that this engine is likely every bit of 280- if not 300 ponies... We'll see how she does... it'll be splashed in the morning.   I'm actually really excited... this engine sounds M E A N...  I may have a 19p 14.125" ron hill pleasure five for grabs- I'm thinking this engine will blow that poor prop out, and I'll be needing at least a 22p wheel of some flavor. 

212rowboat

oh- the whole point of this thread wasn't to brag, it was to offer my ignorance and deliverance from said ignorance... a SINGLE plug wire on a dizzy can spray your spark... who'd have thunked it?  

I didn't need to 'see' the spark after I replaced that one wire... I could HEAR it while turning the key at the helm and this fella grounding it against the block... 

youstolemybeer

congrats, its always the stupid stuff. I once rebuilt a rochester carb because of a horrible miss at low rpm. after the rebuild, still had the miss. it was the plug wires were bad. feces occurs

frodo13056

It's always the little things! About 4 boats ago, I had a 1998 Rinker 206 with the 350 Merc engine with the Thunderbolt V ignition. Decided to do a complete tune up the second season I had it. Went to the local marine parts dealer, got the plugs, wires, cap and rotor - get all the new parts in and off I go to splash in the river for a fun day on the water. I had started the engine on muffs in the driveway and it ran fine - but once splashed and throttling up, thing just ran as crappy as could be. Wandered back to the launch ramp, loaded it back on the trailer, took it home and started troubleshooting. Rechecked plugs, wires, cap and rotor and everything was perfect - so back to the river and same thing - idled fine but would not throttle up. Back home, I took the original parts and put the original cap on, went to replace the new rotor with the old and that when I found that the dealer had given me a rotor for a 6 cylinder engine - not an eight cylinder. Duh. For those that have never replace a Thunderbolt IV or V rotor, the rotor actually has gaps or "windows" for when to spark - not like a traditional rotor. Moral of the story -  now, whenever I get a new part, I always compare to the original part!

Michael T

@frodo13056 Good advice.....and these days it seems to be good advice for any replacement part. The counter guys are often teenagers who wouldn't recognize a screw driver from a pair of pliers.