'68 Johnson 65 hp won't start without fuel mixture sprayed into carbs?

[KJacobsen64]

Hello I am new at boat ownership and my wife and I bought a used 1964 StarCraft 18' boat to play on the lake and so I can do some fishing. It is late in the season but I tried to put the boat in the water a couple weeks ago and the motor would crank but not fire. I brought it home and put the motor in a makeshift tank and attached ear muffs to be safe. I tried different settings for the throttle and thought I may have flooded the engine.. I took out the spark plugs and 3 of 4 were dry and one was a little wet but not soaked? Next I took some fuel from the fuel tank and dripped it into the carbs and it stubble fired then quit, I added more and it fired up but won't idle? I moved the throttle forward a touch more and had to prime the carbs again and it fired up and seemed to run okay but really rough idle?? I am concerned that if I back off the throttle after running it at high speed if it will stall and then not fire again? Is there something I should try to be sure that the throttle doesn't drop to low to keep the motor running or do I need to clean out and possible carb rebuild?

 

[jbjennings]

Re: '68 Johnson 65 hp won't start without fuel mixture sprayed into carbs?

Here's what I would do:
CHeck compression--borrow a gauge
Check spark---$6 at o'reilly's
If spark will jump at least a 1/4" gap with a hot blue spark, then:
Rebuild all carbs. YOur description sounds like the low speed jets are stopped up. I can't remember if the '68 65hp has low speed adjusters on it, but I think it does. YOu may even try opening up the low speed adjusters because they're not set right. There's a procedure in the "top secret file" at the top of this forum for that. Personally, I'd rebuild all those carbs because since the motor is new to you and not running properly, you already know that it hasn't been used in a while. I'd also change the water pump impeller and fuel lines if not new.
Your really need to check compression! It will be an indicator for internal engine problems if you have trouble in the future and need to know what the compression was when it was running good--which it hopefully will be soon. If you have dirty carbs, you may also have dirty high speed jets. If the high speed jet on one carb is a little stopped up, it will cause that carb's cylinder to overheat and ruin the compression on that cylinder.
Welcome to iboats BTW!!
If you're patient and follow the instructions given by the experts here (not me), you will most likely be able to get that old motor into reliable condition and be able to enjoy it for years. If not, you are almost guaranteed that the motor will cause you to hate the boat, and in short order have internal problems with scored cylinders and pistons which won't be economically feasible to repair.
I've been boating with old used boats my whole life and it is extremely rare that I've ever bought a used motor without problems that need to be addressed. On a positive note, I have rarely bought a used motor that couldn't be brought back into good reliable condition far, far more cheaply than buying a new or late model engine. THere have been several threads about those old 3 cylinder OMC outboards lately. F_R is very knowledgeable (understatement) about those 3 cylinders of that time period and mentioned a common problem with the exhaust plate that you should probably check out. I would definitely check compression, and if good, go ahead and remove that inner exhaust plate, replace or re-true it, and replace the exhaust gaskets.
You can do all these things I've mentioned pretty darned cheaply, and will have a much better idea of how your motor works and how to keep it running, so I assure you it will be worth it. Sorry to be so long-winded.....
Good luck,
JBJ

 

[KJacobsen64]

Re: '68 Johnson 65 hp won't start without fuel mixture sprayed into carbs?

:facepalm:

Here's what I would do:
CHeck compression--borrow a gauge
Check spark---$6 at o'reilly's
If spark will jump at least a 1/4" gap with a hot blue spark, then:
Rebuild all carbs. YOur description sounds like the low speed jets are stopped up. I can't remember if the '68 65hp has low speed adjusters on it, but I think it does. YOu may even try opening up the low speed adjusters because they're not set right. There's a procedure in the "top secret file" at the top of this forum for that. Personally, I'd rebuild all those carbs because since the motor is new to you and not running properly, you already know that it hasn't been used in a while. I'd also change the water pump impeller and fuel lines if not new.
Your really need to check compression! It will be an indicator for internal engine problems if you have trouble in the future and need to know what the compression was when it was running good--which it hopefully will be soon. If you have dirty carbs, you may also have dirty high speed jets. If the high speed jet on one carb is a little stopped up, it will cause that carb's cylinder to overheat and ruin the compression on that cylinder.
Welcome to iboats BTW!!
If you're patient and follow the instructions given by the experts here (not me), you will most likely be able to get that old motor into reliable condition and be able to enjoy it for years. If not, you are almost guaranteed that the motor will cause you to hate the boat, and in short order have internal problems with scored cylinders and pistons which won't be economically feasible to repair.
I've been boating with old used boats my whole life and it is extremely rare that I've ever bought a used motor without problems that need to be addressed. On a positive note, I have rarely bought a used motor that couldn't be brought back into good reliable condition far, far more cheaply than buying a new or late model engine. THere have been several threads about those old 3 cylinder OMC outboards lately. F_R is very knowledgeable (understatement) about those 3 cylinders of that time period and mentioned a common problem with the exhaust plate that you should probably check out. I would definitely check compression, and if good, go ahead and remove that inner exhaust plate, replace or re-true it, and replace the exhaust gaskets.
You can do all these things I've mentioned pretty darned cheaply, and will have a much better idea of how your motor works and how to keep it running, so I assure you it will be worth it. Sorry to be so long-winded.....
Good luck,
JBJ

:facepalm: I am not very mechanically inclined and I can probably do the compression check and anything beyond that might require a mechanic or a very good manual to do the work correctly and not make a major mess of this issue. I plan on trying the boat out in another week back at the lake and see what happens I hope nothing bad happens and I can store it and work on it over the winter to overhaul the carbs and check the jets after after I get the manual. Thank you for the advice and I hope to not have to continue blogging with this problem but we will see what happens :embarassed: