First Post! Troubles with 1996 Johnson 9.9hp

[curtise]

Hello Everyone! This is my first thread and I'm pretty excited to see what the community has to offer! I have three problems I'll explain in detail momentarily. I fix simple things on my Jeep (radiator replace, thermostat, plugs, pumps, etc.), so I think I can fix these... hopefully easily! First I'll tell you my setup:

A) Fast Craft 15' fiberglass skiff, late 90's.
B) Johnson 9.9hp hand-start tiller outboard. J10FREDC (on motor mount), J10FREDCU (on engine hood). I'm guessing 1996? Haven't really found a precise fit for this numbering system, everything I see is J10FRED. Am I looking in the right place for the model numbers?

Problems:

1) I included a picture of the throttle body (carb?), taken from the rear facing forward. The white circled lever is frozen partially open. What is it's technical name and what does it do (open/close butterfly valve? Fuel delivery?)? Circled in red is a plastic lever connected to the hand throttle... it (red) only pushes the (white) lever up (open) for throttle and then a spring tensions (white) lever back down to idle, correct? Any ideas on how to unfreeze (white) lever, or do I have to replace it? Tried a leveraging and lubricating it to no avail. Should I take off the throttle body and give it a good cleaning (see question #3)?

2) I put some ear muffs on the motor today and started it up. Peehole shoots water pretty good, but (circled in white) water came gushing out of this hole on top of the lower case. This hole is towards the front and has a rod in it connecting from the upper to lower case. What is this hole/rod and is the water issue normal (don't remember it being this way)? It is open and there is no gasket or seal in between the rod and opening. The rod is also offcenter within the hole. Seems abnormal to me. The pic is blurry, but you can kinda make it out.

3) The past 3 boating seasons this problem has gotten progressively worse: the engine runs great (400lbs of passengers/dogs, 40lbs safety gear and cooler, boat weighs maybe 300 lbs.) for 20 minutes, then overheats. I'll remove hood for a couple of minutes to cool it down. Works good for another 20 minutes. When I leave the cover off, it works great (glass water of course! No waves!). I've had the impeller changed and mechanic said this was the only problem. Seems the motor isn't really getting fresh air- surely it isn't the design of the cover? I took a flashlight and looked into the air intake and there are no obstructions. This overheating problem has ONLY HAPPENED when the boat has a passenger load of over 350lbs. At idle, the motor chokes with the hood on.

I really appreciate you helping me out! I live in Charleston, SC so I just put the boat away in November (long boating seasons here). I'm kinda of excited to work on my motor with mechanic prices around $90/hr. I think I went into the wrong business! I got sick of automotive places ripping me off, so I started fixing my Jeep (2004- shouldn't need fixing this soon!). I'd like to keep my marine visits to a minimum. Thanks and have a great day!

 

[4.0l sahara]

Re: First Post! Troubles with 1996 Johnson 9.9hp

I will just throw this out looks like it's used in salt and that zink annode looks like it needs to be replaced.

 

[4.0l sahara]

Re: First Post! Troubles with 1996 Johnson 9.9hp

Also if the lu oil,water pump and thermostat havn't ben replaced in a few years I would do all three of those things.

 

[curtise]

Re: First Post! Troubles with 1996 Johnson 9.9hp

Thanks 4.0L Sahara for the suggestions (love those I6ers, I've got two, wouldn't trade them). Now that I think about it, I haven't replaced the lower unit oil in a while... what's the frequency on this? Is the water pump an easily install? And, yes, it has been used in salt water. The annodes are bumped; will replace. And the barnacles... let's say I left it in the warm water for month without scrubbing! Two hours of powerwashing and I haven't applied cleaning acid yet... stupid me! I surely have some work this weekend! Now for that pesky throttle body... ugh.

 

[iwombat]

Re: First Post! Troubles with 1996 Johnson 9.9hp

"Seems the motor isn't really getting fresh air- surely it isn't the design of the cover? I took a flashlight and looked into the air intake and there are no obstructions. This overheating problem has ONLY HAPPENED when the boat has a passenger load of over 350lbs. At idle, the motor chokes with the hood on."


I think that last bit is your key to at least one problem. You've got an exhaust leak someplace. And all that overheating will sooner or later (if not already) lead to a head warp and head gasket failure and/or exhaust gasket failure. Take a piece of hose and use it as a one-ear stethoscope to see if you can locate a leak by sound.

Once you find out what's leaking replace the gaskets. Probably a good idea to pop the head , plane that flat and put it back w/ a new head gasket. After all that, t-stats, full water pump and a cooling system backflush.

As it is, you're flirting with a disaster waiting to happen.

 

[curtise]

Re: First Post! Troubles with 1996 Johnson 9.9hp

Thanks for your help, iwombat. I can have my head planed at a machining shop, or does it have to be marine specialized? I had an exhaust leak 2 years ago and it was fixed, supposedly... I've been through 3 different marine mechanics and it seems no one wants to properly remedy my situation. It isn't a terribly complicated motor. This is why I'd like to take it into my own hands. Also, same season, I had a connecting rod failure (sounded like a .308 rifle, I'd call that catastrophic). I'm assuming this is from overheating. On that ride I had a very light load (220lbs- myself and safety gear/cooler). Fortunately some nice guys in a nice Grady twin towed me in. I surrendered my cooler A new connecting rod, new head gasket and (if I remember properly) new piston were all installed. I'm wondering if all of this work is within my capabilities (much higher than average skills and I enjoy it). My friend, an auto mechanic, told me "if you can read a recipe and cook it, then you can work on a car!" He did gripe about electrical problems though! Those gremlins...

 

[iwombat]

Re: First Post! Troubles with 1996 Johnson 9.9hp

You can surface your own head with a piece of glass and some sandpaper. Just tape the sandpaper to the glass and run the head over it with a figure-eight motion. You don't really want it planed, that can remove too much material.

You'll find the mantra here is: Find the source of the problem or you'll be rebuilding again. Looks like that might be true in your case.

That motor is pretty easy to work on. I've completely torn apart a couple of 'em. Get an OEM service manual particular to your year and get cracking. Post any questions you have up here. You definitely want to pop the carb and clean. Wouldn't hurt to put a rebuild kit in while you have it off.

Also, do you rinse off, or coat the powerhead after running in salt? You should probably be doing something. Lots of people just douse the whole powerhead in WD-40. I just wait for it to cool and do a thorough fresh water rinse. Both techniques seem to work fine.

 

[HoochieMama]

Troubles with 1996 Johnson 9.9hp- thermostat?

Troubles with 1996 Johnson 9.9hp- thermostat?

Hi all,

I am trying to confirm a) if I have a thermostat issue, and b) is it an easy repair?

I don't have the "gush" problem here, but I have problem #3 - engine will run great at the dock for a long time ( I had it going for at least an hour )

water coming out of "pee" hole in warm, but steady stream.

However, once I leave the slip, pushing my 2500+ lb sailboat, it never fails that halfway up the river, engine stops working. usually quite unexpectedly, peeing up until the very end. About 45 minutes later, she fires right up on the first pull.

took it into the shop, he could not replicate the problem. He told me that he did run it for a long time, and did have it in gear, but had no way to simulate the load.

What lock did you have curtise with redoing thermostat?
thanks in advance !

Model:Johnson J10FEXEDR
Serial: G04089574