70hp johnson problems NEW CARNAGE PICS

hello guys, im new to outboards but am mechanically inclined and understand troubleshooting, that being said i have a 70hp johnson, its a 94 or 95 cant find the model number or serial but thats another post.

i am having trouble with it dieing and almost acting as if its siezing.

first time up at the end of the day after 4-5 hours of on off use. it goes from full song 5500rpm and winds down to dead in a matter of a few seconds after 5-10 min of running, when i say acts like it siezes i mean the first couple times i hit the key to restart it just clicks and wont rollover. a few seconds (less than a minute) and it started right up and ran my another mile to the dock idled through the no wake zone fine then wouldnt idle at the dock

i changed plugs and fuel filter all very worn and filthy. perform compression check and see between 120-130 across board. run on hose for 30 mins at idle and up to about 3000rpm, didnt know if i should really rev it up or not. during this i used a timing light to check spark and observe it on all 3 cyl

hit the river again, and less than 5 minutes later we are winding to a stop just as before. quite a bit harder to get refired this time, also noticed possible fuel leak/air suck on the fuel hose to quick connect and tighten clamp. then fires up and runs about 10mins or so and begins winding down again, this time is sounds ragged (ticking/tapping not a straight hard knock), and probably missing has shake to support missing, we pointed ourselves to the nearest ramp and called someone to bring us the truck and proceeded to run at plowing speed of maybe 2-2500rpm

through all this i get no warning buzzers bells or whistles. it appears to be using oil from the remote res. the level looks to have dropped some since i filled it when i got the boat 3 weeks ago, and i observed some blueish smoke while running the muffs in the driveway.

im open to any and all ideas and suggestions and troubleshooting ideas. i intend to get a manual of some sort the seloc manuals look to be the boaters version of chiltons or haynes?

i got a smoking deal on this rig and im hoping this motor issue isnt the reason.

Re: 70hp johnson problems

Re: 70hp johnson problems

Get the omc manual, the rest are good for toilet paper. I would check to make sure it is getting oil before you blow up the motor. If it was mineI would disconect it and run premix.

Re: 70hp johnson problems

Re: 70hp johnson problems

You might check and make sure your warning system for overheating is working properly.

Re: 70hp johnson problems

Re: 70hp johnson problems

how old is the water pump? is your tell tale (**** stream) working while out at the lake. water pumps should be replaced at least every 2 years. i do mine every year. their cheap (60-85 dollars) and not hard to do, about 2 hours work.
on a hose or not in gear 3000 rpms is the absolute highest you want to go. i'd keep it below 2500.
take a garbage can, put the engine in the can and fill it with water. then run your engine. the earmuffs with hose has pressure which will not show if your pump is working so by doing this you can eliminate the pump. it could also be a bad thermostat. but like davit said make sure your overheat horn works first before replacing the thermostat.
it could be a host of other things but this is where i'd start off.

Re: 70hp johnson problems

Re: 70hp johnson problems

i'll try to address all that,

i was considering switching it to premix, perhaps i should have i fear it may be too late.

checking warning systems is high on list need to locate the how to on that.

age of water pump is unknown, i've only had it 3 weeks, as for tell tale stream its pretty good from what i can tell, and running down the river doesnt get what i would call hot. reached back and had tested it while running, and actually during yesterdays adventure as well.


NOW, i just visited the boat and pulled plugs and did a compression test again and found some not so good stuff.

top 140lbs, plug looked good a bit wet

middle 40lbs electrode on plug bent down touching center electrode. NOT SMASHED appears to be JUST touching. plug also wet but looks to have crumbs of unknown origin on it.

bottom 140lbs again a touch wet but good looking

i would attribute the wet look on the plugs to the slow limp back to the launch, i know 2 strokes are prone to plug fouling at low rpm.

things to note,
all pistons move when turning the engine,
piston on middle cylinder does not look to have a mark on it from contacting the plug nor does the plug look to have been physically hit, and yes im certain that the electrode wasnt bent when i put it in the other day.

im no genius but im guessing its gonna be a rebuild due to a cracked piston/ring or the scrap heap due to cracked cylinder bore

anyone have a how to on testing the warning systems for temp and vro system?

i did see mentioned that the vro makes a noise when you turn the key on? mine makes a sort of boooyp tone for a second. not sure where the noise maker is but sounds like its coming from the console.

what might i expect to pay for an overhaul? just looking for a worst case scenario

Re: 70hp johnson problems

Re: 70hp johnson problems

a few pics including the offending plug

still trying to determine exact year/model, so any ideas there are welcome

http://community.webshots.com/album/577969029MqRnOq

Re: 70hp johnson problems

Re: 70hp johnson problems

if you feel confident you can do it yourself, you can buy a complete powerhead for about $2000. if you are really a gearhead you can rebuild your powerhead for $500-800. you can take it to a mechanic for $3000-4000.
since your other 2 cylinders are really good (140 sounds good to me but check the manual or someone else can verify) you can just re-ring the one cylinder. probably cost you less than 200 in parts for a diy. again solve the problem before you fix the engine. from the sounds of things you blew a ring due to a carb not working. does not sound like a vro problem cause the other 2 cylinders are in good shape. but if you'd like to test the vro take a gas line off the carb, put it into a clear bottle and crank the engine. if the gas comes out colored with whatever color your 2 cycle oil is your vro should be good. if its clear-yellowish not good.

Re: 70hp johnson problems

Re: 70hp johnson problems

A couple of things to try, leave all plugs out, install a properly gapped plug in #2 cylinder and rotate flywheel by hand 3 or 4 complete revolutions, remove plug and recheck plug gap. If gap is still ok, install plug and spin with starter, remove plug and check gap. What you are trying to see is if the piston is hitting the plug at lower RPM. If the plug gap changes, you are looking at an overhaul to correct problem.
With 40# compression in #2 cylinder, it might be a goosd idea to remove the cklinder head and look for damaged cylinder, piston or head gasket.
If the piston is hitting the plug, you will be able to see it with the head removed.

Re: 70hp johnson problems

Re: 70hp johnson problems

i presume there are water passages through the head, that only flow water once the thermostat opens? wondering if this may explain why it seemed to run ok to begin with untill it warmed up perhaps?

daviet i can try those things easy enough, im a but leary of pulling the head but only for the reason of if i need to take it to someone it may make them turn me away.

i assume since a carb problem was mentioned that the crankcase is divided so each carb is in fact responsible for its own cylinder alone. this actually seems good from a reliabilty standpoint.

if i pull the thermostat and heat it on the stove what temp am i looking for?

if the head gasket is blown to a water passage putting the hose and muffs on with the 2 plug out i would likely get water to run out the plug hole correct?

where and how much should i expect on the omc manual?

Re: 70hp johnson problems

Re: 70hp johnson problems

You can PM " Intermediate Mariner "
he has the manual online. in PDF files.
hope that helps!

Never mind I found his link
http://mobileoncallmechanic.com/boats_ and_trailers.htm
goodluck

Re: 70hp johnson problems

Re: 70hp johnson problems

thanks for the link, but i dont see anything that covers my year...

im not 100% on the year but i did see a date code on the block of 3/1994 so i assume its a 94 or 95

are the seloc manuals at least decent? i know from the car world that the factory service manuals cover things better than chiltons or haynes but they are tuff to come by

if i get time saturday im going to pull the plugs again, and perform the contact test suggested above

and maybe pull the head as that seems pretty idiot proof, and take a look in the cylinder, and for a blow out in the gasket and take off the airbox and take a peek and the carbs an see if that #2 is super dry or something obvious

gotta decide what to do here. on the upside i have a quarterly bonus check coming in a couple weeks, wouldnt cover a reman but should buy the parts for me to do it, the costs given above absolutely blow my mind, seeing as this is a 2 stroke with very few moving parts unless im mistaken

Re: 70hp johnson problems

Re: 70hp johnson problems

ken cook would have that manual and it is a must. It's gonna cost you. Mine was 78 bucks but you get what you pay for.

Re: 70hp johnson problems

Re: 70hp johnson problems

did some exploring today, and found the damage and a possible cause..

fuel line to middle carb is split i couldnt make it leak by pumping the bulb but it is all wet inside the split rubber, and the bottom carb is drenched in fuel/oil residue

i pulled a line and pumped the bulb to obtain a fuel sample which came our blue greenish so im guessing vro is working ok.

piston is destroyed sleeve is scored pretty badly, and the head is likely junk also it looks similar to the piston, but no missing pieces i had a pic of that too but my phone ate it i guess

on the up side the other 2 cylinders look good, no scarring or lip and i can see cross hatch very clearly. so it might be a low hour unit, or a recent rebuild that a 50 cent piece of fuel line managed to ruin


not to sure what to do now, will prolly call around monday and see what some places say and go from there

Re: 70hp johnson problems

Re: 70hp johnson problems

morning bump for the carnage pics,

does it seem plausible that the burst/leaking fuel line caused the cylinder to go lean, get hot, detonate, and attempt to sieze?

Re: 70hp johnson problems

Re: 70hp johnson problems

dmoriarty51 said:

morning bump for the carnage pics,

does it seem plausible that the burst/leaking fuel line caused the cylinder to go lean, get hot, detonate, and attempt to sieze?

Click to expand...

Yes.

Re: 70hp johnson problems

Re: 70hp johnson problems

dmoriarty51 said:

did some exploring today, and found the damage and a possible cause..

fuel line to middle carb is split i couldnt make it leak by pumping the bulb but it is all wet inside the split rubber, and the bottom carb is drenched in fuel/oil residue

i pulled a line and pumped the bulb to obtain a fuel sample which came our blue greenish so im guessing vro is working ok.

piston is destroyed sleeve is scored pretty badly, and the head is likely junk also it looks similar to the piston, but no missing pieces i had a pic of that too but my phone ate it i guess

on the up side the other 2 cylinders look good, no scarring or lip and i can see cross hatch very clearly. so it might be a low hour unit, or a recent rebuild that a 50 cent piece of fuel line managed to ruin


not to sure what to do now, will prolly call around monday and see what some places say and go from there

Click to expand...

Ouch!

If the head is pitted from bits of the broken ring/piston most machine shops can clean that up. Hopefully the cylinder can be bored out enough to fix that scoring.

I rebuilt the same motor and documented a bunch of it online here. Check out the link below to the thread for some idea of what your about to go through.

http://forums.iboats.com/showthread.php?t=361179

Cheers

Re: 70hp johnson problems NEW CARNAGE PICS

thanks for the link, that honestly doesnt look all that tuff nor complicated

seems like getting my hands on the parts at reasonable prices could be the tuffest part really.

i earlier assumed that the cylinder bore was a sleeve that was likely replaceable, as i thought the crancase to be aluminum.

it appears that im wrong on that one? they must be bored, and at some point become un boreable and the case is thrown out? or is that the point when it would be resleeved?

Re: 70hp johnson problems NEW CARNAGE PICS

it can be resleeved if nessasary.
that head may be repairable.
only place I use for outboard boring and sleeving is Ron's marine and eqipment in portsmouth VA.
he has been doing it over 30 years and has done all mine since abot 1989.
UPS delivers.
remember whoever bores or sleeves it must be knowlegeble about correctly chamfering the ports when done.

Re: 70hp johnson problems NEW CARNAGE PICS

well, i had a guy look at it today, and he beleives the roughness in the bore is mostly poston melted to it, and that it should clean up ok, however that the head is junk he is getting back to me monday after he gets prices

so at this point it looks like its getting rebuilt rather than dumped off a cliff.

most likely going to switch to premix ro avoid future VRO issues... which will be a pain since the boat has a built in tank but i'll figure something out to make it easy for me

Re: 70hp johnson problems NEW CARNAGE PICS

something you should know. your problem is most likely not caused by bad vro. i just had a friend whose 1997 115 had the exact same thing. the rod bearing flew apart, got sucked into the chamber then blew apart the piston lodging pieces into the head. the vro was disconnected for at least 10 years. just something to consider before disconnecting it.