Looking for some insights and new ideas regarding a suite of issues we've been having on an atomic4 w/ no known history we inherented. Detailed most of our work history & troubleshooting below. Help save us from the temptation of tossing on an outboard.. pleeeeease!!
Too long? Didn't Read?
"professionally" installed motor has had increasing number of issues in course of 3 months/6 sails. 2 fateful sails punctuate: (1) sudden shut down after bypass left fully open by accident, wire on coil found unconnected, which was reconnected and engine hard started; (2) where engine stalled, steamed, & knocked.. had to paddle into slip after restarts stalled almost immediately
Original thought was overheating, causing steaming/paint chipping, found metal scaling pushed against t-stat housing (see attached photo).
Can't find a blockage, up until manifold (haven't looked in there yet).
2.5qts of dark, decent looking oil removed on oil change.. slight swirling discoloration, but no metal/no choco milk.
Rattling or knocking getting worse, faint when idling/increasing w/ throttle, flywheel visibly stutters, seems to diminish if wire pulled on plug3 (worse if pulled on plug1?).
IR readings show temps w/in normal range (90-140F), up until manifold exit which jumps to >350/400+ (before cooling down to 80F when expelled.
---Boat---
27’ 1976 O’Day, New to us, 2 previous owners that neither really sailed
RWC motor with no known history, was bought offline “rebuilt” & replaced existing a4 (likely hooked direclty up to existing/original exhaust set up)
motor was given to previous owner, who “didn’t last long in boat ownership"
---Sail History---
-PO had motor installed at boatyard; new prop/prop shaft installed; good compression (90-100+ in all cyls).. last line of invoice reads: “trouble running in boat; timing? alignment? fuel?” -PO sails 4+ hrs, before they shut the motor down for smoke/steam(?)
-Towed ashore by coast guard; timing “adjusted” on feel by someone else; PO $pooked & $ells boat
-We motorsailed it back 20nm to home port; w/o apparent issue.
handful of issue-free sails, aside from slight stalls changing gears,
Next few sails issues emerge..
--First --
(Bypass valve left open by accident)
Motors to sea fine, sail for 2 hours fine, starts up fine & motors 10-20min
Sudden involuntary shutdown on the water, no start & steam out of manifold/flame arrestor, plastic smell
crank no start w/ seacock open 5-10times, reconnect some wires on the coil (maybe melted lose?) and hard start before motor back to dock at v.Low RPMS;
first instance of audible rattle (1 cpt heard faint indication when pulling out slip), seems to originate closer to flywheel end
Changed plugs, inspected impeller & raw water system, no issue.
Ran in gear at slip for 30min, Bypass valve half closed, IR readings normal.. except at manifold exit, >350F
rattle/knock sound audible, less w/ wire pulled off 3rd cyl
—Second--
Go to sea, lots of crew, pups too, motor out the slip w/ stalling when gears change
Sail for 45-min, turn around for weather
Motor starts, runs poorly.. aggressively increasing knock-sound, steam in cabin,
Motor stalling & rattling loudly, pups spooked, hot at manifold exit
Full stall prevented by throttling up, limped into slip with one final stall/shutdown
Pull apart cooling system, t-stat removed, tested, and opening
Remove intense amount of scaling (large pieces included) that was slammed up against the passage bw t-stat housing and head (see attachment)
After a delay, we flushed FW extensively, bypass closed w/ FW running in Water Pump, out T-stat Hoses
Flushed clean water on 2nd 5gal bucket, magnet attracting exceptionally fine metal dust
Warm engine again w/ rattle/knock, warmer at manifold exit,
change oil.. 2.5 qts removed.. dark, decent-looking.. swirling discoloration? no metal on magnet; replaced w/ 3qts sae30
Compression test again, basically same numbers.. 100-100-90-95
Rattle/knock diminishes w/ wire pulled on cyl 3; intensifies w/ wire pulled on cyl 1.
Both of us feel the noise is more audible from forward portion of engine.. rather the aft end by cys 3&4/manifold exit
—Status--
Not really sure where to check next.. nearly about to toss a outboard on the back unless we get some good ideas
Motor turns over well, seemingly plenty exhaust water expelled w/ bypass 3/4 closed, but continues stalling when choke closed (i.e. leaner mixture), waiting on new fuel filters
Save us from the temptation of slapping on an outboard!!
Need ideas to troubleshoot next!!
We're ready to go sail!
Too long? Didn't Read?
"professionally" installed motor has had increasing number of issues in course of 3 months/6 sails. 2 fateful sails punctuate: (1) sudden shut down after bypass left fully open by accident, wire on coil found unconnected, which was reconnected and engine hard started; (2) where engine stalled, steamed, & knocked.. had to paddle into slip after restarts stalled almost immediately
Original thought was overheating, causing steaming/paint chipping, found metal scaling pushed against t-stat housing (see attached photo).
Can't find a blockage, up until manifold (haven't looked in there yet).
2.5qts of dark, decent looking oil removed on oil change.. slight swirling discoloration, but no metal/no choco milk.
Rattling or knocking getting worse, faint when idling/increasing w/ throttle, flywheel visibly stutters, seems to diminish if wire pulled on plug3 (worse if pulled on plug1?).
IR readings show temps w/in normal range (90-140F), up until manifold exit which jumps to >350/400+ (before cooling down to 80F when expelled.
---Boat---
27’ 1976 O’Day, New to us, 2 previous owners that neither really sailed
RWC motor with no known history, was bought offline “rebuilt” & replaced existing a4 (likely hooked direclty up to existing/original exhaust set up)
motor was given to previous owner, who “didn’t last long in boat ownership"
---Sail History---
-PO had motor installed at boatyard; new prop/prop shaft installed; good compression (90-100+ in all cyls).. last line of invoice reads: “trouble running in boat; timing? alignment? fuel?” -PO sails 4+ hrs, before they shut the motor down for smoke/steam(?)
-Towed ashore by coast guard; timing “adjusted” on feel by someone else; PO $pooked & $ells boat
-We motorsailed it back 20nm to home port; w/o apparent issue.
handful of issue-free sails, aside from slight stalls changing gears,
Next few sails issues emerge..
--First --
(Bypass valve left open by accident)
Motors to sea fine, sail for 2 hours fine, starts up fine & motors 10-20min
Sudden involuntary shutdown on the water, no start & steam out of manifold/flame arrestor, plastic smell
crank no start w/ seacock open 5-10times, reconnect some wires on the coil (maybe melted lose?) and hard start before motor back to dock at v.Low RPMS;
first instance of audible rattle (1 cpt heard faint indication when pulling out slip), seems to originate closer to flywheel end
Changed plugs, inspected impeller & raw water system, no issue.
Ran in gear at slip for 30min, Bypass valve half closed, IR readings normal.. except at manifold exit, >350F
rattle/knock sound audible, less w/ wire pulled off 3rd cyl
—Second--
Go to sea, lots of crew, pups too, motor out the slip w/ stalling when gears change
Sail for 45-min, turn around for weather
Motor starts, runs poorly.. aggressively increasing knock-sound, steam in cabin,
Motor stalling & rattling loudly, pups spooked, hot at manifold exit
Full stall prevented by throttling up, limped into slip with one final stall/shutdown
Pull apart cooling system, t-stat removed, tested, and opening
Remove intense amount of scaling (large pieces included) that was slammed up against the passage bw t-stat housing and head (see attachment)
After a delay, we flushed FW extensively, bypass closed w/ FW running in Water Pump, out T-stat Hoses
Flushed clean water on 2nd 5gal bucket, magnet attracting exceptionally fine metal dust
Warm engine again w/ rattle/knock, warmer at manifold exit,
change oil.. 2.5 qts removed.. dark, decent-looking.. swirling discoloration? no metal on magnet; replaced w/ 3qts sae30
Compression test again, basically same numbers.. 100-100-90-95
Rattle/knock diminishes w/ wire pulled on cyl 3; intensifies w/ wire pulled on cyl 1.
Both of us feel the noise is more audible from forward portion of engine.. rather the aft end by cys 3&4/manifold exit
—Status--
Not really sure where to check next.. nearly about to toss a outboard on the back unless we get some good ideas
Motor turns over well, seemingly plenty exhaust water expelled w/ bypass 3/4 closed, but continues stalling when choke closed (i.e. leaner mixture), waiting on new fuel filters
Save us from the temptation of slapping on an outboard!!
Need ideas to troubleshoot next!!
We're ready to go sail!
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