96' Johnson 30hp- I just cant get this motor to run right

[KB976]

temp sounds OK. Should be testing on the top of the cylinder head (top of the top cylinder). The face of the head around the plugs is normally hotter -- your 146/148, I take it (at which point the top of the head would probably test a bit cooler). Anyway sounds good to me. Others may have an opinion.

you did a "drop cylinder" test -- appears both plugs firing, so good there too, at least at the rpms tested.

consider condition of fuel -- contamination/water in fuel could give you symptoms described.

yeah, i did the test at what i would consider the top of the engine (although due to how the engine is mounted it is the side). like I said, it had the laser dot about a 1/4" from the spark plug hole. that's where i got those readings at.

yeah, i did the drop down while it was running, pulled one plug at a time, had a substantial drop each time so im confident each cylinder is firing as it should at idle.

I was concerned about the fuel, so for the past week and a half, i have been running a brand new tank with new 91 octane fuel (no alcohol), and new quicksilver 2 stroke outboard oil, 50:1 ratio. there is achance the fuel is bad, but I doubt it as it was a BP station, and the same symptoms come from my older tank as well.

 

[KB976]

someone local suggested running a hotter plug,, not sure how that would help here, any thoughts?

 

[oldboat1]

doing it right, so far, seems to me. No addit. ideas for you at the moment....

 

[KB976]

well, I really appreciate yours and all the other members help. Like i said initially, this engine has me stumped and at a loss, I know two strokes pretty well, but for some reason, boat motors just take it to a whole new level. I have already priced other motors... but that just isn't feasible. so, hopefully I can get onto the right direction with the guide of these members.

 

[jakedaawg]

It certainly sounds like fuel to me. Is there any chance you got the float in upside down when you rebuilt the carb? The divit, or groove in the float is the "up"side. At this point it is worth tearing down down to check. Sorry, but needs to be checked as the bowl of the carb has a rounded portion and logical thinking would be to put the float in upside down.

 

[oldboat1]

didn't see your post re. plugs. IMHO, doesn't sound like the answer -- although probably wouldn't hurt to give it a try if the heat range isn't radically different. Thinking you might be dealing with a safety feature on that motor, that might be misbehaving (little too "new" for me). Hold out for some additional lister input.

 

[jakedaawg]

usually in one of these an upside down float just leads to surging at high speed, but, if installed upside down and with an incorrect initial alignment, I could see the problems you describe happening. I have found more than one of these by guys who tried to do it themselves and actually did it once myself way back! Remember, when you have that carb flipped to install the float the carb is upside down so anyways the groove in the float needs to be facing the body of the carb not the bowl.

 

[jakedaawg]

sorry for all the posting but I want to add a disclaimer.....All of the 30 and 35's I work on are older than this one so the carbs/floats may have changed, so the description I gave may be inaccurate. Maybe one of the experts will chime in here. I do know that even in that year it is possible to install upside down but I haven't had a late 90's apart in a couple of years.

 

[jakedaawg]

K, was wrong, I just dug out the manual and the divit in the float faces down in your model

 

[KB976]

No worries, I was pretty sure I had it right. I used the blown-up view from this site.

 

[jakedaawg]

So it is installed correctly? If so I am out of thoughts. It is quiting because the bowl is running out of fuel. If pumping the bulb does not help it is a float height or improperly installed float or air leak/fuelrestriction or clogged or partially clogged bowl vent.

 

[KB976]

So it is installed correctly? If so I am out of thoughts. It is quiting because the bowl is running out of fuel. If pumping the bulb does not help it is a float height or improperly installed float or air leak/fuelrestriction or clogged or partially clogged bowl vent.

I took of the carb again to check, this float can only be installed one way. Also, I checked the float level, i was told to do this by holding the carburetor upside down and ensuring the float sat level.

Where is the bowl vent?

Where could an air leak come from?

 

[jakedaawg]

well, if noone else is gonna chime in here we need to start back at the basics. Do you have an air gap sprk tester? if so test for spark at 7/16" gap with fast idle fully advanced.

 

[KB976]

I do have an air gap tester. What do you mean by fully advanced? what RPM rang do you consider fast idle?

 

[AlTn]

is it possible that it's getting unmetered air into the intake through the primer system?...if you want to check, just slip the hose off the intake nipple and plug the hose off, make another plug with a piece of fuel line with a bolt, screw, dowel, inserted into one end so that it's air tight then clamp the other end to the intake nipple. It would be best to do this on a warm engine so a restart doesn't take as long. If this makes no difference, at least it's eliminated a possibility. Sure sounds like the fuel bowl isn't staying full for some reason.

 

[KB976]

is it possible that it's getting unmetered air into the intake through the primer system?...if you want to check, just slip the hose off the intake nipple and plug the hose off, make another plug with a piece of fuel line with a bolt, screw, dowel, inserted into one end so that it's air tight then clamp the other end to the intake nipple. It would be best to do this on a warm engine so a restart doesn't take as long. If this makes no difference, at least it's eliminated a possibility. Sure sounds like the fuel bowl isn't staying full for some reason.

Im on the same page as you and jakedawg, I think the bowl is running out of fuel. I wil try this test tonight as I have not done this yet.

Along the same lines, can I test flow by pulling that same line and not plugging it? I would think I should see a pressure change on the output of fuel as I ramp up the rpm's. is my theory right here?

 

[geoffwga1]

As someone just said,this motor is a bit new for me so not sure about the carburetor.Having said that,two possibilities spring to mind .#1 the float needle is sticking closed for some reason.#2 there could be an air leak round the low speed needle,check the packing.

 

[jakedaawg]

Was the carb kit an OEM kit?

 

[KB976]

As someone just said,this motor is a bit new for me so not sure about the carburetor.Having said that,two possibilities spring to mind .#1 the float needle is sticking closed for some reason.#2 there could be an air leak round the low speed needle,check the packing.

The float needle is rubber tipped and therefore does stick a bit, its brand new ordered with the carb kit from this website. The old float needle was rubber tipped as well and also stuck a bit.

below is the break down of my carb. where is the low speed needle? this is a slightly different layout in only two ways, #6 is on the bottom where they show #13 going, and their is nothing where #6 is. no hole or anything.
What is the packing that you are refering to?

 

[KB976]

Was the carb kit an OEM kit?

I don't know for sure, it was from this site which has the "Evinrude/Johnson Genuine Parts" logo at the top of the page. Also had the same logo on the packaging, so I assume so, but can't be sure,