just got this boat/motor. it ran poor from the start. loads of water
in fuel seperator and did the following.
- dumped old gas
- replaced all fuel lines, from tank thru to carbs
- cleaned and rebuilt all carbs, including new high & low speed jets
- new spark plugs ( gapped correctly )
- new spark plug wires
- rebuilt fuel pump
- replaced one of 3 coils
- installed tach
- compression check ( all with 10 of 110 )
- checked timing, ( is it really just stop screws )
got boat to start well, idle well, run well up to 4000 rpms then it bogs down.
squirt pre mix into top carb at wot and motor would jump up to 5500 rpms.
same story with holding in primer solenoid. jumps to 5500 rpms.
- cleaned all 3 carbs again. this time soaked in mineral spirits for 20 mins
and worked them with a toothbrush. blew them clean with compressed air.
put it back together, started motor with muffs in driveway, a little hard to start but ran okay at idled to 2000 rpm for a good 10mins
took boat to water, backed it in, lowered motor in water. motor would
not start. waited 15 mins. shot some starting fluid into carbs, motor
started. ran on trailer in water for 10 mins, then pushed her off
and headed out. got up to 5500 rpms for about 30 secs, then she died.
got it started again, and limped in at 1500-2000 rpms. lots of coughing,
gasps and choking the entire way. anything over 2000 rpms she'd die.
my current thinking is, fuel problems are now solved but there is now
a spark problem. i have ordered a new powerpack and will install it
and test again this friday.
my question: - am i grasping for straws with the new powerpack, does it
really seem like there is a spark issue, what else should i look for, consider,
do or test ?
Port Charlotte FL but never the same since hurricane Charlie
Re: 1985 70hp Johnson - HELP !!
Personaly I'd only opt for changing (expensive) ignition parts if I was sure it had no spark. But only after I ran the tests to make sure I was replacing the correct component.
If holding the primer in and / or squirting fuel into the carbs cures the issue I'd say you still have a fuel delivery problem. I'd start by soaking the carbs in carb cleaner. You say you installed new kits, we'll assume the floats are set correctly and are free. We'll also assume you didn't forget the round gasket over the emulsion tube.
You mentioned the water separator, have you checked it again for water / debris? Also make sure you have the correct Champion plugs.
don't wish to appear harsh here but as dhadley has mentioned, if you hold on the choke or squirt fuel into the Carby it runs OK (well sort of) so why do you come to the conclusion there is a spark issue? not saying there isn't but just think about it for a second!
seems like my post was not completely clear. there was a 2 step process.
Step 1. Did everything listed, but soak and clean carbs with toothbrush.
Results were, easy start, great idle, runs fine to 4000 rpm . wot bogs, squirt pre mix or hold primer solenoid jumps to 5500 rpm. obviously not the way
she's supposed to run, so i keep trying.
Step 2. Soaked and toothbrushed carbs, hit 5500 rpm WITHOUT squirt or primer push for 30 seconds. then died and ran worse then ever, poor idle,
dies at anything above 2000 rpm, engine coughs, barfs, chokes, sputters.
thinking is, fuel supply problem now solved but now have spark problem.
sounds like carbs still picking up trash any time you introduce external fuel to carb and it picks up it means that your not getting correct supply
check your spark under load on trailer with timeing light
when the prob occurs you will see the miss by looking into timeing light
when you hit primer your motor should bog down not pick up sounds as if you have fuel prob run differnt tank and hose. bypass fuel filter if ya have one in line ,if that doesnt get it back off with the carbs pull welch plugs and jets
soak overnight , blow with compressd air , i know you have had them down a couple of times but sounds like you have restriction in jetting.
i pulled a carb five times with high speed bog finally took it to my boat guy
i sonic cleaned it and used compressed air with small tip on it
also had heavy float but that would cause over gassing on plugs what do your plugs look like
I fixed the fast idle problem, it was the power pack. One of
the pins was bent a little in the rubber boot and not making
a good connection. I also put three new spark plugs in
and gapped them all to .035
I got her running great with muffs, then took her to the
water. She started fine and I took off, ran at WOT 5600 rpms
for a minute or so.
Then she bogged down, started to cough, sputter back fire,
slog, choke, etc.... anything above 2500 rpms and she'd die.
I tried some pre mix in the carbs during this and it made no
Anyone have a opinion ?
It would be great to hear from someone with experience.
This is my first boat and first time I've worked on a
a motor since high school shop class 30 years ago.
I am not a mechanic, but if spraying pre-mix in the carb did nothing I think you can rule out a fuel delivery problem. Sounds more like an electrical problem to me.
If I'm wrong I am sure someone will correct me, and even if I'm right I am sure they will give more insight into what to check out and/or fix. I'm about as new to this as you.
Hello to you,
Is it overheating on you, maybe that is why it runs at 2,500 RPMs after it heats up. If not get a hair dryer and warm the coils up one at a time and see if heat is causing the coil to go out and thus losing spark on bad coil. Check your spark plug wires and make sure there good also no cracks, detoriation, dry rot etc. Also make sure your coil grounds are clean and shiney as well as all the gronds on the motor, nice and shiney clean. Hope this helps you out somewhat without having to buy pars and put them in to find out it is another part and waste money. Let me know, Bob
Bubba - No idea if it's over heating or not. There is no temp gauge
so I have no idea about what the temp is. I don't even know where
the thermostat on the engine is. Can you tell me where that would
be located ? I'd like to inspect and see what it looks like.
The spark plug wires are all brand new, I will check for shiney grounds
plates on coils and the other grounds on the motor.
i have a similar outboard (1990 60 HP) that had the same symptoms yours is having. Also: i did the same damned thing with replacing power pack, fuel delivery etc etc.
MY problem was a crack in the lever of the primer solenoid. the problems was hard to catch because fuel would only leak under load and while powering up.. Just a thought of something else to peek at - I spend ALL THIS PAST SUMMER replacing electrical components, fuel delieveries, rebuilding carbs, etc etc.
I'd take an inductive timing light and a helper with you next time out on the water. When the engine starts to act up, check each of the 3 plug leads for spark. Check when the engine is under load. Hopefully, all 3 with show constant, rhythmic strong flashes. Look for intermittent or no fires. If you see problems, there are two other ignition components you have not mentioned checking, the stator and the timer base. Each can be checked electrically (with special tools and the service manual) and can contribute to the problems you mention. Electrical problems seem to show up once the engine reaches normal operating temps. All the ignition components are expensive, so a good upfront analysis is cheaper than just replacing components at random. I don't think the 85's had the SLOW system yet, so the pack should not be limiting revs to 2500.
jblaiz - how did you find the crack in the primer solenoid ? i've had mine apart
and nothing jumped out that was obvious. of course i was not looking
for a crack... also, if i squirt pre-mix in the carbs and it makes no difference
do you think it's safe to rule out fuel delivery ?
emdsapmgr - beyond, power pack, coils, plugs, wires , " timer base & stator "
are there any other components ? would a bad thermostat contribute to
my symptoms ?
I doubt the thermostat is the cause of any of your problems, but a laser temperature gun would help determine if it is functioning propely. If the thermostat is stuck open, the engine will run cold. Cold running engines will smoke more and can accumulate carbon around the rings over a long period of time. If the thermostat is stuck closed, you will get an overheat horn at idle after just a few minutes. You did not mention any of these symptoms as being a problem.