Carb Adjustment needed?

[shoot2retrieve]

I've have just recently gotten a new to me boat from family. It has been well taken care of and winterized at the end of every year. The boat has an 85 Johnson V4 140 Horse 2 stroke (Oil gas mix). Has been serviced for the spring. Will start on high idle but will then die. Use the primer bulb and it will start right back up. If it is trying to die and can quickly pump the primer bulb, it will surge back until it has burned the fuel. So to me I have identified a probable fuel delivery problem, correct? Now should first thought be carb adjustment, fuel pump? If so is there a web site that would show an illustration on carb jet screw location or need to get service manual? Also noticed a small tube or wire on the front side of the motor down on the lower unit that came out and looped back in the was broken. Is this for speedo or what is it purpose? Thanks for any insight!!

[yarcraft91]

Are you using the right starting procedure? IIRC, that motor has an electrical fuel primer system, like my 1991 120 Johnson. The procedure for mine is to push in the key and hold it there while cranking until the motor starts. If I don't, the motor will start, rev briefly then die. Pump the primer bulb and you can repeat this over and over.

If you're using the right starting procedure, check the primer and fuel pump systems. Hold off on the carb adjustments, in fact, there may not be any on your motor.

Some other thoughts- when the motor was put away last Fall, was stabilizer mixed with the fuel and run through the engine?

[perchjerker]

I have a 94 200 Johnson and came up with a better starting procedure. Works better for me, anyway...

Pump the primer ball hard, then turn the key to the run position (dont crank it) and hold it in for 5 seconds. This opens the primer solenoid and allows fuel to squirt into the intake until the pressure from the primer bulb is gone. But sometimes this does not provide enough gas to the motor.

So I repeat this procedure 2 more times. Pump, hold the primer in for 5 seconds, repeat this two more times before cranking. Mine fires up right away after that.

Before, i used to crank and crank the cold motor hoping it would start.

A few other guys I know now do this and it works for them too.

[staylor]

and yarcraft91 and perchjerker both gave some good tips. I had an '84 140 and usually after the motor started the bulb would stay hard. Since your bulb seems to be losing its prime the first thing to do is to re-check when idling with the motor warm and running. If it still can be pumped then I'd look for a leaky hose or bulb, and then to the VRO unit as the source of the problem. Depending on how your motor is rigged, you may have a quick disconnect on the fuel line at the motor that will allow you to test with a remote tank and bulb that you know is good. If not, then re-check/re-tighten every connection in the fuel line between the tank and the motor. If you find any conventional hose clamps- the metal kind, then replace these with the OMC plastic clamps from a dealer- plain hose clamps tend to pinch the line and tiny air leaks develop over time. When you do this, it will work better if you remove the line from each connection, cut off a half inch of line, and then put the line back on with the new plastic clamps. While doing this, replace the bulb itself since these also leak internally when they get old. If the hose itself seems stiff and brittle, then replace the entire assembly- using the new gray colored alcohol resistant hose rather than the old black hoses from the '80s. If this doesn't work, then the problem is usually in the VRO. Check all VRO screws for tightness- if you see any drippage than there's a leak someplace. The older VROs had to be replaced as a unit, but Bomb may have repair kits available since OMC changed their policy on rebuilding back in the 1990s. The OMC V-4 and V-6 engines also had a very detailed procedure to set up the linkage to open the carbs. If your motor needs adjustments then this could also be part or all of the problems. The only other item I can think of would be that the carbs have crud in them and this is blocking an idle jet- although this problem seems to happen more to the V-6s than the V-4s. OMC had a very detailed manual on these engines. The manual may still be available from you dealer. If not, then the manuals were published by the Ken Cook company- out of Wisconsin if I recall correctly. They are still offering these manuals today. Just go to www.outboardbooks.com and put in your year and model.
Doug

[GBS]

I may be off base here - but I might suggest a whole different course - change your plugs. My '00 115 Johnson two stroke was doing close to the same thing last spring. I could get it to idle, but giving any gas and it would die. Would appear to run off of prime if started at high speed. I started to chase fuel delivery issues. At the suggestion of WC'ers, I put in new plugs, and it was magic - motor ran perfectly right away and for the rest of the season.

Cheap fix, and something you probably would want to do any way!

[yarcraft91]

Adding to Staylor's comments-

Carefully check every single clamp on your fuel and oil lines (of course, check oil lines only if you still use the VRO system). When I did that this spring, I wound up replacing 3 of the black plastic OMC SNAP clamps on the fuel line. They looked OK, but when I tried to gently wiggle them it was obvious they were broken. That can allow the fuel pump to suck some air, not a good thing. Fuel line clamps size SNP 10 or 12 worked on my 3/8 fuel line, cost about 50 cents each at a dealer. That experience shows why it pays to check all the fuel line connections at least once each year.

Another tip on that motor, if you haven't already done it, check the torque on the bolts holding the carb main bodies onto the throttle bodies and the throttle bodies onto the intake manifold. When I did that on the '91, I found the majority (17 out of 24) were looser than spec, some more than 1/2 turn. That invites air leaks and a bad idle. Be sure to use the right torque specs and technique- if you have the "Type IV" carbs as I do, the specs are 42 in-lb for the main-body-to-throttle-body bolts and 120 in-lb for the throttle-body-to-intake-manifold bolts. If you have the right tools (e.g., an inch-pound torque wrench, not a rachet) and know how to use them, this is a simple job- if not, I don't recommend this as a place to learn. Messing up the plastic carb main bodies can get expensive (>$150 each).

[shoot2retrieve]

Thanks, guys I'll give it all a try. Start simple and if that fails go more invasive. Wish I could do it today and run water off the hose w/ muffs but supposed to get down to 22 degrees tonight. Kind of worried that might freeze and give me a whole different problem!! As far as stabilizer I think plus ten was used and ran thru. Fuel from then has been dumped and brand new fuel put in. Thanks again.

[perchjerker]

excellent advice!