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Older 45 Johnson Sputters Badly under Load

B

big_builder

Contributing Member
Hello Everyone ,

I have a 45 Evinrude Tiller ( commercial type) mixed gas. Two cylinder.

I will look up the exact model number today and post. I guess it would be late 80's.

IT's condition is this. It will start fine and idle fairly normal. IT will leave the dock and begin to plane as usual. Then as it begins to plane or shortly after it planes it will begine to cut in and out . The sound would be b est described as NAA> NAAA> NAA>. Squuezing the ball seems to have no affect. If I throttle down I can putt back to the dock OK. If I put it in neutral and rev it up it sounds a little rough but it will rev right up.

When this condition happens increasing the throttle makes it worse and the motor lurches badly as the power comes on and off.

I am thinking this is someone electronic since it happens so sharply ....but I can't figure out how the disgnose which part it is. Individual componets are fairly pricy and I can easily spend more than the motor cost me throwing parts here and there.

Anyone have any ideas or procedures that might help me?

Thank you
 
Start with a compression test. When you have those results you can advance to repair work.--------------------A compression test is the first thing to do in trouble shooting most faults.
 
Sounds like the carb needs to rebuilt or cleaned out.Main jet has some sort of blockage or float and needle are messed up.When you are throttling it up you are advancing the ignition as well, without the gas that is required, hence the sputtering.
 
Ok. Thanks for those tips.

Checking a carb is no problem at all for us but It doesn't seem to be fuel related. I can see right in the carb while running and it seems to be getting consistant fuel.

May I ask how to use a timing light on a two stroke. Done many times on cars and trucks but I have never tried on an outboard?
 
Unless you have a flow meter and can check the amount of fuel delivered and what the specs are then I would start at Mr.Carb. There is no way humanly possible to do a visual inspection and deem that that is the right amount of fuel being fed to the motor.I just had a free 1965 18 hp act the same way,off to the bench it went. Yep it was loaded up with crap, ran fine in the garbage can and coughed like you described on the boat under load.START there and report back.
 
The timing light is used as a " poor man's scope "-------------Observe the flash, a steady flash on #1 means good ignition .------Then repeat on #2.
 
Ignition related problems usually cause a "jerky", erratic miss while fuel related problems are usually a smooth loss of power as the throttle is opened wider. You could put some pre-mixed fuel into a squirt oiler and squirt it into the carburetor when the problem occurs to see if it makes a difference. If it is missing on a single cylinder and you can keep it running long enough, you will be able to feel a temperature difference by touching the cylinder head. The cooler cylinder is of course the one that's missing. If you can run it at night with the cover off, you can also visually check for spark leakage from bad wires. Good Luck.
 
I have a 1973 Evenrude 40Hp and had trouble with the engine doing the same jerky reactions.. I rebuilt the carbi and cleaned it out and since this it has stopped playing up, mind you I had already replaced the plugs and checked and adjusted all the electrics. I found that the needle and seat was worn baddly and the fuel bowl was full of crap.. I also found that when the water pump went once it did the same thing as the engine got over heated. anyways hope these help.
 
Your rev-limiter/SLOW is kicking in.
Try disconnecting the temp switch on head and see if that helps.
try another power pack.
 
Model Number?

Spark plug make, ID#, gap? Plug appearance identical?... describe. Water traces on either plug?

Rather smooth change of rpms = fuel..... sharp rpm change = ignition. Your engine has sharp change?
 
This is definately not a smooth loss of power. We have lots of outboards and have experinced our fair share of bad puel pumps ( squeeze the ball all the way home) and air leaks and plugged hoses etc. This particular problem happens when you start to throttle up and plane. It is an immediately loss of power then a jerk as it powers up for a second and then totall loss again. To best describe it in words it is a jerk on /off jerk on/off. Just keeps doing that until you let right up on the throttle. You can then putt all the way home. The whole thing is very dramatic and seriously jerky.


I think I might try the night time boat ride tonight....
 
So this is what I have looked at so far. Carbs look very clean inside, fuel filter is spotless, plugs look excellent ( were new this year) lower unit oil was clear and clean but I changed it anyways.

I still need to run it in the dark to see if there is any sparks flying. I will also try and disconnect the temp sensor wire at that time to see if that affects it too.

I will keep posting as I work through this. I have spare coil and power pack from another motor I can try too.

Thanks everyone.
 
So I continue to work on this motor. I am struggling. So to date I have cleaned the carbs, checked the hoses, lower unit, newplugs, new kit in fuel pump and it still sputters. But today another thing came up. Looks like there is a samll head gasket leak. I am not sure if this is related but I got a new head gasket and want to put it in. IS there anything special I should know about installing ti or is it straightforward? THe local evinrude dealer isn't able to locate the model and serial number on their database. IT is a 45 evinrude commercial tiller. Model CE45RWLU Serial number C7241209

ANy help as always is appreciated.
 
There is a water jacket cover on the cylinder head and that may be leaking.----------Changing a head gasket is fairly straight forward, just a few bolts.-------------Just make sure the head is flat ( resurface it using a piece of glass and some emery paper ) when you re-install.-------Tighten bolts in 3 steps , starting in the middle and working out . final torque to be 240 inch lbs. --------retorque after test run and engine cool down.
 
Racerone thank you. I am going to take the boat out tonight ( it's my work boat) can I ask you another questions? It looks like the leak is coming from the gasket clossest to sparks plugs....is this a water jacket gasket of is this the head gasket? Do the bolts require any special treament...like silicone sealant when they go in? OR just put the gasket on and torque as you described?

Thanks for all you h elp.
 
My bet is that it is not the head gasket , just the water jacket gasket.------------1/4" bolts-----------nothing special ----------torque to 80 inch lbs.
 
The only thing special is that if this engine is used in salt water you usually need to be very careful removing the bolts, and frequently need to heat them, in order to get them out without wringing them off and causing all sorts of other problems.
 
Yes a salt water like all of mine. My Dad brings them back from the East Coast (NFLD) for us. Retired fishing motors. We like them because they all use tillers there.... we even have a 130 hp yamaha tiller!

Everythnig is hard to remove though.
 
Are you sure your main pinion and forward gear isn't skipping out. When I first got my 35hp johnson it started doing this and I didn't know what it was so like an idiot I kept driving it and it got worse until one day it just wouldn't go any more. I took the lower end apart and the main pinion gear was smooth. I mean literally just a hint of gear teeth. So this also ruined the forward gear as well. I replaced both gears and good as new. I'm not sure why this starts but neglecting it is definitely a proven bad idea. I hope you get it figured out. Good luck.
 
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