Johnson 35 cranks, but will not run.

[flintcreek]

I bought a 16' Lowe Hustler with a 35 Johnson motor 1977 model not running a couple of weeks ago. Finally got around to starting to work on it this weekend, cleaned the carb. Cranked it up and it goes dead. Ok, choke it, the motor will hit a lick but not start, let the choke off and it will crank and run for 30 seconds or so. If you give it gas it will sometimes run a little longer. Again choke it, the motor will cough and try to start, let the choke off and it will start and run for a minute or so, backfire and die. I have tried 2 different fuel tanks and 2 different fuel lines. Hopefully I can get my son or someone to help me tomorrow and try to pump the bulb while it is running, to see if it is the fuel pump. Any Ideals?

 

[cajuncook1]

I bought a 16' Lowe Hustler with a 35 Johnson motor 1977 model not running a couple of weeks ago. Finally got around to starting to work on it this weekend, cleaned the carb. Cranked it up and it goes dead. Ok, choke it, the motor will hit a lick but not start, let the choke off and it will crank and run for 30 seconds or so. If you give it gas it will sometimes run a little longer. Again choke it, the motor will cough and try to start, let the choke off and it will start and run for a minute or so, backfire and die. I have tried 2 different fuel tanks and 2 different fuel lines. Hopefully I can get my son or someone to help me tomorrow and try to pump the bulb while it is running, to see if it is the fuel pump. Any Ideals?

Well, since this is used but new boat to you and you were aware that it is none running, there are some steps that you should take.

You will see a lot of experience guys ask about compression, spark and fuel. (They are using a systematic approach to diagnosing an engine problem or problems....in this order)

C= compression ( if your compression is low are uneven between cylinders >10% then others checks don't matter until the that is resolved) (This is very important the previous owner could have run this motor and overheated and damaged the pistons or cylinders or the head gasket could have blown)

S= Spark (if your have problems with your ignition then you can have the cleanest carb and great fuel delivery but it will run bad or not at all) (Bad coil, spark plugs or even bad power pack assembly) **Check spark on both cylinders**

F= Fuel (if your carbs are not clean and fast/slow idle needle are not set right then it will run but like crap. If you have it set too lean then you run the risk of poor fuel/oil delivery and damage your pistons and cylinders then you run into the problem of C (poor compression from damage).

When you clean a carburetor make sure you get a kit and take out all of the core plugs, because gunk and junk and can block up the 3 tiny holes under the core plug for the slow speed idle needle.

So get a spark tester ($7)and compression gauge($12 to $14)

Here are few links for good reading and assistance.(to see the pictures on the iboats forum you can join the forum just like this one and yes it is free)

https://www.tinboats.net/forum/viewtopic.php?f=4&t=14047 (will give a link to a public library that has condense facts and manuals regarding your motor)

https://forums.iboats.com/showthread.php?t=158071 (why it won't start)

https://forums.iboats.com/showthread.php?t=167352 (carb adjusting)

https://forums.iboats.com/showthread.php?t=244013 (carb cleaning and rebuild)

https://forums.iboats.com/showthread.php?t=313963&highlight=compression (compression testing)

https://forums.iboats.com/showthread.php?t=283363 (How to test your boats fuel system...there is alot of detail in here)

Well I guess this will keep you busy for a little while!!! I hope it something simple!!

cajuncook1

 

[flintcreek]

Cajuncook, thanks for the reply and links. Here is a update on where I am.
My compression gauge had somehow went bad, I borrowed one and the compression is 130 on both cylinders. Bought a gap type spark tester and the bottom coil is weaker than the top, but still jumps spark about 1/2". Appears to be a fuel problem, I took the carb down and it looked perfectly clean, so I did not go on through it. However I have ordered a carb kit and it should be in this morning, so later today I will be going through the carb. I may also go ahead and change out the fuel pump for a known good one and borrow a fuel tank and hose so I will be able to eliminate those also. I will post again when when I get a little more checked out. I do know that when I spray a proper fuel and oil mix in the carb it will run. Hope to have it running today.

Thanks,
Flintcreek

 

[Zum]

Did you ever get someone to pump the bulb,to see if it would run?
Your last statement makes me wonder,that all.

 

[cajuncook1]

Cajuncook, thanks for the reply and links. Here is a update on where I am.
My compression gauge had somehow went bad, I borrowed one and the compression is 130 on both cylinders. Bought a gap type spark tester and the bottom coil is weaker than the top, but still jumps spark about 1/2". Appears to be a fuel problem, I took the carb down and it looked perfectly clean, so I did not go on through it. However I have ordered a carb kit and it should be in this morning, so later today I will be going through the carb. I may also go ahead and change out the fuel pump for a known good one and borrow a fuel tank and hose so I will be able to eliminate those also. I will post again when when I get a little more checked out. I do know that when I spray a proper fuel and oil mix in the carb it will run. Hope to have it running today.

Thanks,
Flintcreek

Make sure your float in the carburetor is working properly. The float could be the original and may not be working properly, so it doesn't float up when to the bowl is full to stop the introduction of more fuel or the float valve/needle could be stuck or junk up.

If your kit comes with a float then replace the old one. The the newer ones withstand the effects of ethanol in the fuel. If you didn't get a new float your kit, check to make sure that the old still works(doesn't matter if it looks old). To test the old float, place it in a cup/can of premix fuel and see if it floats. If it doesn't then you need a new float.

Use a can of carb cleaner with spray straw and spray each hole you can find. Remember when you disassemble the carb take the core plug/plugs out and clean in their well. Remove all plastic parts!!! Carb cleaner will dissolve coatings and plastic in a heart beat!!!

Do the carb cleaner spray outside (the fumes of that stuff is harmful when done in doors and wear goggles)

***If this is your first carb kit job. Use a digital camera as you are taking it apart to help you remember later if you run into problems remembering how it goes back together.

Here is a link of a diagram of your carb (think it is the right year and make)

https://www.boats.net/parts/search/BRP/EVINRUDE/1977/35702C%201977/CARBURETOR/parts.html

Go to: https://search.ebscohost.com/

Log in with:

Name: marshall

P.W. : public

-----Go under the Small Engine Repair Reference Center

-----Then select Marine/Boat motors

-----EVINRUDE/JOHNSON

-----OUTBOARD 35 HP (1976-1989) or

-----OUTBOARD 2-40 HP, 1973-1990 (INCLUDES ELECTRIC MOTORS)

A way to check if a fuel pump is going bad (raise the tank(portable) to the level of the carb or slightly above to see if the motor will maintain running. Or you or someone else can pump the bulb when it starts to kill.

Hope this helps some!!

cajuncook1

 

[flintcreek]

Carb Kit did not come in until today, so I did not get to do much to it Saturday, but I did check and the fuel pump seems to be good. When I pumped the fuel line bulb it did not make a difference. The garden was growing up so this afternoon instead of work on the motor after I had to till the garden and work in it. Now I am about too tired to mess with the motor, so instead I am in here in the cool on the internet. We will see I may still go out and see what I can do before dark to the carb. Thanks guys for the advice and links.

Flintcreek