First day out didn't go well

[Kelly]

I got the boat out on the lake today. Made it about a half mile from the access when my engine, Force 4hp, died. When it died, the tiller handle literally flew out my hand and the engine jerked sharply to the left. I turned around to see smoke rolling out from under the cover and I could hear a sizzling sound. After letting the engine cool down, it was really hot, I can't get it to fire. I pulled the head of and the cylinder walls look good, no gouges or scratches. I kind of understand the basics of a little two-stroke but I'm a diesel mechanic and these things are too small! Any help would be greatly appreciated. This thing needs to be running very soon, spawn is just around the corner.

 

[Waterwings]

Sorry your motor crapped out. I'm not a mechanic, so I have no suggestions, but do hope you get it running before the spawn.

 

[bassboy1]

Sounds like you overheated it due to lack of water (I assume your oil was mixed correctly). Your water pump impeller may have finally bitten the dust (they wear out after 2 - 3 years - less even if the engine is not used frequently) and it wasn't pumping the needed water to the engine. When you say you aren't getting it to fire, are you saying that you can't get it to start again, or you checked, and you aren't getting spark (being a diesel mechanic, you probably don't check that very much :lol: )

 

[Kelly]

I have spark, but the engine won't start. Where is the pump? I'm guessing it is in the lower end, but I don't see where that comes apart.

 

[bassboy1]

I have spark, but the engine won't start. Where is the pump? I'm guessing it is in the lower end, but I don't see where that comes apart.

Yep, should be on the top of the lower unit. I am not familiar with the Chrysler/Force motors (by choice), but every other outboard in the world is going to be like that. There should be a seam somewhere above the prop, and the lower unit comes off there. You have to disconnect the shift rod, and that varies by model. I don't rightly have a clue how it comes off on that motor. On the J/E motors, there is a little access plate on the side of the midsection that comes off, and you get to the shift rod bolt with a nutdriver.

 

[Kelly]

Oh yeah! The impeller looks great. But then I decided to pull it out anyway to see bottom side of the impeller and I pulled the drive shaft out of the lower unit. Heard a clunk and already knew what I had done. So right now the oil is draining and I am about to tear into the lower unit to attempt to fix the problems as I create them. I am not enjoying this, that's why I keep coming in to the computer.

 

[bassboy1]

Hmm. So, your oil was correct, and your impeller was good. There was still a reason for an overheat, so after you fix the lower unit, you probably need to make sure there is nothing clogging the water lines. Was the woodruff key still in the impeller?

 

[Kelly]

Woodruff key? There is a cross pin that goes through the shaft and catches a hole in the bushing of the impeller. Could there be mud in the tube? The lower unit came apart like butter and it's back together now. I'm getting good at this! OK that's not true.

 

[Captain Ahab]

Kelly - you should have a "tell" - a spout of water that shoots out to "tell" you that the water pump (impeller) is working - no water means no pressure means overheat = very bad

You could have a clogged intake or bad thermostat

 

[Kelly]

This thing has a thermostat? Where would it be? What does look like?

 

[Captain Ahab]

This thing has a thermostat? Where would it be? What does look like?

i am assuming it has one - most outboards do - looks similiar to an automotive one - usually found above the impeller


Keep in mind that I deal with 150 hp outboards so maybe the little guys do not have thermostats? BassBoy1 - HELP

 

[ben2go]

It's doubtful that it has a t-stat.The cooling tube that runs from the impeller housing to the engine could have broken loose or be leaking.This would keep water from circulating through the engine correctly.Have you checked ebay for a repair manual?That would be of great help.You could see how things are designed before tear down and inspection.

 

[ben2go]

Just found this.Give it a try. https://www.outboardrepairs.com/force_outboards_by_horse_power/

https://www.repairmanual.com/marine/3/448

 

[redbug]

I keep reading the original post and wonder could it be an electrical problem ?
you said something about sizzling just a thought..

 

[ben2go]

There shouldn't be any electrics on that motor.Just the coil(s),the coil trigger(s),and kill switch.It should be a jerk start engine.

 

[bassboy1]

Keep in mind that I deal with 150 hp outboards so maybe the little guys do not have thermostats? BassBoy1 - HELP

I rarely, if ever deal with these, so I am unsure if that motor in particular has a thermostat. I know some of the mid 90s 15 horse motors did, and just about all that were bigger than that did, but I couldn't tell you on the 4.

I am really running out of ideas here. While I can't tell you the specifics of that Force, these smaller 2 strokes from that era are all identical in the way they operate, and they are utterly simple. You have fuel and oil, mixed at a 50:1 ratio, and the oil lubricates all the moving parts. Then, you have water, being pumped from the lake, through the motor, that carries heat made by the motor away. That's it. So, if your oil was mixed correctly, we can eliminate that.

So, that leaves water. Now, your impeller was good, and presumably the Woodruff key was installed correctly, so hypothetically speaking, you should be pumping water. Since you can't get it to run, we can't determine whether or not it was pumping correctly. You almost have to have a thermostat that died in the closed position, or another clog somewhere in the water lines. Other than that, there really is nothing that could go wrong.

Due to the lack of any real wiring these motors have, I can't really find a possible way for the electrical to cause that issue. As ben2go mentioned, you only have the coils and such that give it spark. Outboards do not get the electricity for the spark plugs from a battery or anything, as a car would, and they just make it with the spinning magnets in the flywheel. They are usually killed by shorting out the charge that would go to the spark. So, if there were wires that had burned up, unless they somehow magically remained suspended, the place where the insulation burned off would touch the block, shorting it out, in essence doing the same as a kill switch does. Since he has spark, we can rule that out.

Now, once we get it running, we can determine whether or not it is pumping water (I can already tell you it isn't, because they don't just decide to overheat by themselves, and short of oil, there is nothing that could go wrong with it). But, first, we need to backtrack, and figure out how to start it again. Since you have spark, all that is left is fuel. The only thing I can come up with right now (I will probably have a better idea in the shower or something), is that when you overheated it, you melted a carb gasket, which blocked a passage off.

Sorry, but that is the best I could come up with.

 

[Kelly]

The idea about the water hose sounds logical. When I had the lower unit off I saw a pipe that ran down from the power unit to the water pump. The tube looked good, but I could only see the last couple inches of it. The was also a short tube, three to four inches, that dropped down and stopped. I'm guessing that was the hot water exit. I can't see either of these tubes on the top side, I'm guessing they run into the bottom of the engine case. After giving some serious thought to my fuel mixing routine, I am now skeptical. This engine has the fuel tank built in, which holds just over half a gallon. So I take a one gallon fuel can and put the correctly measured amount of oil in the can, then go to the gas station for exactly one gallon of 91 octane. I buy 91 for it's lack of ethanol. In this area 87 and 89 both have ethanol, at least they did before oil prices crashed. Anyway, I sat the freshly filled fuel can in the stern of the boat and headed for the lake, filled the tank while I prepped on the ramp. Ten minutes later I cussing in the middle of the lake. I'm wondering if the oil didn't mix with the gasoline since the temperature was only 54 yesterday. Does this sound logical? By the way, the engine started right up this morning in the driveway in a barrel. It ran for probably twenty minutes in neutral with the throttle barely cracked. I didn't notice any problems or excessive heat. I'm going to check the library for a Clymer manual tomorrow.

 

[ben2go]

From what I have been told by an OB mechanic,your engine doesn't have a thermostat.The only engines he was sure of tha did was 15HP and up and the derated 9.9 and 10 HP that some companies put out.So your engine should have a water cooled head and exhaust.Here is how it's supposed to werk.Water enters the lower unit intake ports,travels through the water pump,up the water tube,through the head to the exit port in the exhaust.The exhaust cools and pushes the water down through the collumn (part between the lower unit and power head),and out a port above the prop.My 1980 gamefisher 5hp just has water cooled exhaust and collumn.The power head is aircooled.The way the impeller and housing is made,it's easy for debris to be pushed up the water tube.It narrows slightly where it enters the head and this is where blockages are usually found.They way the mechanic does his is with a long gun cleaning brush.Just gotta pull the lower unit first.The tube is just a slip fit into the head.I use a small drop of rtv to seal my water tube.