yet another catastrophy!

[tschamp20]

this makes the 8th problem in 9 trips ive taken w/ this motor.
today after i launched got to the end of the no wake zone trottled her up ran strongest it ever has ran.even got 5000 rather than the normal 4800 rpm.about 30 seconds later i slowed down to hook up depth finder and noticed a miss.turned around to head in since i was so close.then i noticed the telltale stopped flowing completely.shut it down.had steam from the telltale.i made the decision that since i was only about 500 yards from dock to start it up and get in. but to my surprise it was peeing again,for about 10 seconds then stopped again.it ran that last time for about 15-20 seconds w/ no pee.
after getting to dock i checked the heads w/ my hand and it was BLAZIN HOT!
when i got home checked compression,110-115 on all four.
found #2 plug electrode was pushed down,which i assume caused the miss.
put in the surface gap plugs i have as spares and it started right up,and peeed.shut it back off.
im gonna drop lower unit tomorrow night to check impeller.
obviously the heat sensor is defective.
could a failed impeller cause the intermittent flow that i saw?
as a reminder this is a newly rebuilt 1973 johnson 115.every ignition part is new,i mean everything!
all passages were cleaned out as well.
any other things i should check?
oh yeah its also a new thermostat
thanks for reading ,DOUG

 

[kenmyfam]

Re: yet another catastrophy!

I would have suspected thermostats not opening. Did you put them in right ??
Check them in hot water to make sure they open at the correct temperature.

 

[Silvertip]

Re: yet another catastrophy!

Absolutely a defective impeller will cause tell tale flow issues.

 

[hoeser]

Re: yet another catastrophy!

If your tell tale is cutting out it is likely the impeller (or a clogged tell tale hose...). Thermostats have nothing to do with tell tale flow.

What do you mean your #2 plug electrode was pushed down? You mean it had zero gap? How would that happen short of mechanical damage? I hope I'm just misunderstanding this.

One last thing, if you are only getting 4800rpm out of this engine you are lugging it, might want to consider changing the prop.

 

[tashasdaddy]

Re: yet another catastrophy!

hoeser, surface gap plugs do not the the standard electrode that projects from the plug, the are just that fixed flat surface plugs, and have been used in outboards for many years. some people like them some don't. i do. but if you do a lot of slow speed running, trolling, you should use the proper standards plug with the adjustable electrode.

 

[tashasdaddy]

Re: yet another catastrophy!

tschamp20, i just had a brand new sierra impeller disintergrate, on the first try. spun right off the brass bushing, and went to pieces. never pumped a drop of water, and yes it was installed properly. i suspect my another motor has the same problem.

 

[hoeser]

Re: yet another catastrophy!

Tashasdaddy: Yes, I realize what surface gap plugs are - I've used them in my 140 but was never pleased with the performance. The way I understood it is that he had standard plugs in (like QL77JC4's), one of the gaps got shut somehow, he then went to his backup plugs, which are surface gap plugs.

 

[tashasdaddy]

Re: yet another catastrophy!

sorry hoeser, now that i reread it. i agree with you. i reread it while ago and missed it. hopefully someone dropped it when installing.

 

[hoeser]

Re: yet another catastrophy!

Yes, scary. The last time I saw a plug with a closed gap it was caused by a piece of the ring getting in between the piston and the plug

Hopefully it looks nothing like this.

 

[tschamp20]

Re: yet another catastrophy!

it looked exactly like that,as a matter of fact the #4 plug did that once before. i have a feeling the head has been resurfaced pryer to me.i think i will go with the surface gaps so as to eliminate that problem.i know i got the rod bolts torqued right when i rebuilt it.hell one conn rod and piston and bearings are new.and its the one that hit this plug.
i really hope its not another ring job.although every bolt is new or cleaned and will be very easy to disassemble.
still didnt get to taking off lower unit.as a side note i had the thermostat out last week to fix a stripped adaptor plate bolt.it felt and looked like a clean reinstall,so ill be checkin that as well.
i will follow up tomorrow after i get into it.l8r

 

[hoeser]

Re: yet another catastrophy!

Well if it looks exactly like that, it's a ring that let go. Your piston alone wont make an indent like that. You'll have to check compression to be sure.

 

[kenmyfam]

Re: yet another catastrophy!

Those pieces jammed in the plug have to come from somewhere and if one piece has broken away you can be sure there are more to follow.

 

[tschamp20]

Re: yet another catastrophy!

what in the world would cause a brand new ring to break already.it has maybe 5 hrs of total running on it.we were careful when installing.

 

[tschamp20]

Re: yet another catastrophy!

hoeser i just noticed your pic is of an autolite 2634.thats the same type of plug that was damaged everytime.never the l77jc4 plug

 

[Solittle]

Re: yet another catastrophy!

Did you repalce the deflectors when you rebuilt it? That could be part of the heating problem. The other is more serious though.

 

[Marc III]

Re: yet another catastrophy!

Use the recommended Champion plug only. Don't trust cross reference charts.

 

[tschamp20]

Re: yet another catastrophy!

update: pulled lower unit and impeller looks brand new,no cracks what soever. glad i took it off though the exhaust housing to l/u seal was misaligned.
took apart thermostat and VOILA!! i broke the nipple off when fixing stripped bolt last week.i felt a click when reassembling last week but though it was the nipple indexing into the hole on relief plate domed cap thingy.lol
also took off port cylinder head.ive got a little pitting.im kinda thinking i didnt remove the pieces of imbedded rod bearing that were in the head and they dislodged.not much play or slop in either piston.i guess time will tell.like i say compression is 115 on both cylinders.
i called napa to see about vernatherm they say they dont carry it.but they as well as ishopmarine show my vernatherm as being for 3 & 4 cylinder 1985-1990. whats w/ that?anywayz hope im getting this thing under control.i so badly want to have confidance when going out on the water!

 

[hoeser]

Re: yet another catastrophy!

tschamp, the plug in the picture is an L77JC4.