'97 35HP Johnson "kicked up" but didn't hit anything

[hdefjunkie]

Hey all,
I was wondering if anyone experienced this before. Was going along and the engine started to bog ever so slightly and then the outboard "bucked" up like I had hit something and the engine shut off. As I understand, this is by design.

However, I didn't hit anything at all. I looked very hard for deadhead etc... Then started it right up and continued on my way. It's happened probably 3-4 times over the years.

I was wondering if something in the gearcase or driveline could cause this?

 

[JB]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

If your engine abruptly stops while underweigh just the drag of the foot can kick the engine up.

I think your more important question should be why the engine stops so quickly for no apparent reason. Sounds like something is seizing, then releases after a few minutes.

 

[81 beachcomber]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

had this with my old chrysler, bad connections would trip the breaker and shut it off, only happened when the motor was under load getting on a plane or fighting waves and what not. Just the forward motion of the boat would kick the motor up,

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Doesn't the engine quit (by design) if it bucks up? Funny thing is.. it will run fine for weeks, sometimes months until it happens again. Very strange. Only happens at WOT as well. With a slight bogging down just before it bucks up..

I was also thinking about drag since the motor trim was all the way down, so raised it a hole and put a little weight in the front to stop the bounce. Gonna give that a try and see what happens.

Maybe the gears in the driveline aren't meshing fully?

 

[jtexas]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

nah, lifting the motor won't shut it off -- a prop strike will stop it though.

As long as the motor is pushing the boat, it will stay down unless something lifts it.

If the gears were partially but not fully meshed, you'd know by the clattering sound.

 

[Silvertip]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Next time you are in the boat and cruising kill the engine and quickly stick a paddle in the water. Forward movement of the boat will tend to pull the paddle rearward does it not??? You have propeller that was pushing the boat up until the time the engine quit. With the unit in gear, the prop acts just like the paddle and the forward movement of the boat through the water forces the engine up. Remember the equal and opposing forces session from your HS physics class?

 

[boobie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

The last time I seen this happen was when the mtr was running too lean on oil or hardly no oil in the fuel. The mtr would slow down and then have a seizure kicking it up. Any water in your fuel?

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Hmmm.. electrical connections, low oil & contaminated fuel.. Thx..Some areas to investigate. This unit is equipped with 2stroke oil injection. I suppose it could be possible not "enough" oil is being delivered under WOT/load. I've had low oil alarms but was normal since the resovoir need to be filled. A flaky oil or fuel delivery problem at high speed perhaps...

 

[jtexas]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

If it seized due to inadequate oiling at hi speed, the damage will show up in a compression test.

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

If it seized due to inadequate oiling at hi speed, the damage will show up in a compression test.

Good point on the compression test. I've always thought of a seize as binary. Either the engine is seized or not.. Haven't heard of a temporary seize..

 

[boobie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Is this mtr by chance a 35 hp 3 cyl????????. If it is get rid of the oiling system on it and mix your fuel 50:1. Unless the damage is already done.

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Is this mtr by chance a 35 hp 3 cyl????????. If it is get rid of the oiling system on it and mix your fuel 50:1. Unless the damage is already done.

Yep, it's a 3 banger..Guess a compression check is 1st order to see what we're dealing with. It's 2nd hand so really unsure about it's history but disabling the auto oiling sounds like a good idea. Funny enough prior to the event when the motor kicked up, I did some really heavy towing and the OB was working pretty hard... encountered no problems.. not even overheating. Sucked up the oil out of the resovoir just fine. Looks like the parts or replacement mixing value isn't available anyway so rebuilding the value doesn't seem to be an option.

I see mention of disabling the auto oiling system, sounds like it's just a matter or re-routing the fuel lines effectively disabling the mixing value.

I have service manuals but not handy at the moment. Just wondering what kind of compression should I be looking for?

 

[jtexas]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Anything upwards of 100 is ok, as long as all cyl are within 5% of the average.

3-4 occurences over some number of years, and runs normal otherwise -- tough to troubleshoot when you can't replicate the symptoms.

In the "top secret file" at the top of this forum, is a link to a thread describing how to disable the oiling system. Might want to test the overtemp horn while you're at it.

 

[boobie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

As per the OMC service manual as long as the cyls are with in 15 psi with each other they are okay. Just for kicks stick your nose in the oil tank and see if you can smell any fuel. Remove the oil tank and mixing valve and do a little fuel line plumbing. Just pop the low oil connector off the tank and that will take care of that system. Don't forget to mix your fuel 50:1.

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

Well thought I'd update this one since I started it . Was out to the cottage and the OB kicked up again a couple of times.
Tried to pull start and was locked up solid. Waited about 5 minutes and the engine started and was able to get to the dock. Disconnected the automatic oiler and everything is fine. For those who called it, great advice.. Motor was definately seizing. Maybe this will help someone else. Checked compression and was 120psi on top cylinder and 150psi for the other two.

Feeling pretty lucky considering

 

[boobie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

You've got 30 psi between the cyls. OMC says max of 15 psi. Don't feel to lucky yet but you may want to mix 24/1 in your fuel and run it for awhile. The damage may be already done but I don't want to be a "I told you so" so I won't.

 

[hdefjunkie]

Re: '97 35HP Johnson "kicked up" but didn't hit anything

You've got 30 psi between the cyls. OMC says max of 15 psi. Don't feel to lucky yet but you may want to mix 24/1 in your fuel and run it for awhile. The damage may be already done but I don't want to be a "I told you so" so I won't.

Yah, I mixed with 50/1 and ran it quite a bit over the last few days. No unusual noises,
knocking or excessive smoke other than on first start. But that was not out of the
ordinary. Guess time will tell how much actual damage was done apart from the 1 cyl.