1979 115 gas mix coming from the exhaust and under the cowling

[papachaz]

Hey all, me again. I'm going to start over.....

I traded for this procraft bass boat with the 79 Johnson 115. it started and ran fine at the previous owners house. He told me it would run but had a 'cough' occasionally. When I put it in the water the first time, ran it about 3 miles up to my favorite fishing spot and back. It did cough a time or two. It was very cold natured, but giving the nature and age of the beast, no big deal.

After putting it back on the trailer, I noticed gas/oil running down the leg, on the front side. Pulling the cover and looking, the fuel lines were dry rotted. Took the carbs off, changed the fuel lines, didn't mess with any linkage, put the carbs back on. Ran fine on the muffs. Took it to the lake and it wouldn't run when in the water. I kept fooling with it and got it to run one time, but it would never pick up and run full speed. Kicking myself for not rebuilding the carbs while they were off, I came home, and went a few days later and picked up carb and water pump kits.

got them all put back on yesterday. It will start and run, as long as I have the fast idle lever pulled up. It will NOT idle. as it warms, I can back it down to around 1100 rpm, it will surge as it runs, eventually will go dead. And I still have fuel mix running down the leg and out the exhaust. Haven't done a link and sync yet. if I can't get it to ldle, I can't really do that can I? I have set the linkage and throttle cable according to the manual, yet no luck.

something is causing it to flood and fuel mix to run out, it was doing it before but at least it would run, now I've done something to it and it won't even run.

One question. I haven't picked up a timing light yet, i've read through the threads here on link n sync as well as the manual, how do you adjust the timing? I'm supposed to set it 4 degrees btdc to start with, that's what the threads here say as well as the manual. I know on my truck, I'd turn the distributor, no idea what to do to get the white lines to line up? as always, any and all help greatly appreciated

 

[Rapio]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

This is very hard to help with online. Just too many possibilities. E.g. Carbs float setting?? 1100 rpm isn't all that high on a water hose if you could close the throttle. In gear in the water it will slow down considerably. Yes, 4 degrees is a BTDC is a starting point for idle. The timing advances by spring loaded linkage as you move the throttle forward. Ensure this arm linked to ring under the flywheewl moves full forward freely. Do this with the engine shut down. I would suggest the full rpm timing be checked only with the boat in the water. I'm talking from a 1980 and hope it is not too different.

 

[emdsapmgr]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

You may a a couple of issues going on. Priority to investigate first: Possible that the powerhead base gasket has failed. Common problem on older V4 crossflows. The exhaust will leak into the cowling when running. Spent fuel (black, tarry substance) will leak into the cowling and down the midsection. Once that happens, the leaked exhaust gas inside the cowling can get recirculated back into the carbs and that will affect running. To verify the leak, pull the cowling and test run it at the lake.

 

[papachaz]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

@rapio - thanks for the try. It will not idle, no I can't close the throttle, if I do it goes dead. I can back the fast idle lever down to about 1100, but that's not closed all the way. As for the floats setting, I leveled them parallel with the carb body and did the
'I can blow air through in operating position but not if I turn it upside down' test as described in the 'secret files sticky carb cleaning and rebuild' wouldn't that suggest they're set right?

emd - thanks for those suggestions. I'm figuring its going to be something like the gasket, which isn't something I can fix myself. This is unburned fuel I have running down the lower unit though, not burned or partially burned. I'm going to start it up in a bit and make sure I check all the hoses, lines and fuel pump for tight connections/leaks there.

Thanks again guys, not my first rodeo here, just a different horse.

 

[papachaz]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

I pulled the carbs back off, just to check rabios suggestion of float adjustment. When I took the bowls off both carbs, the core plugs were laying in the bottoms. Apparently I didn't get them seated and that I'm sure is part of the problem, if not all of it. I would like to clarify float height though. So I have the carbs upside down, and I want to line them up with the body of the carb. I do this by bending the metal, correct? do I want the top (when it's mounted on the motor) even with the carb body, or the other side. Meaning the whole float would be above the carb body, so that would be down in the bowl when mounted on the motor, right? is this with the gasket laying there or without? I just want to make sure I get this right, I'm becoming way too adept at taking these things off for my liking, LOL.

all help appreciated!

 

[emdsapmgr]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

When you reinstalled the core plugs, did you also re-seal them?

 

[papachaz]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

I seated them with a bigger hammer this time. I think I put them in upside down the first time, which means that they didn't expand out to the edges and seat correctly. I've had it running, cranks, runs and idles now just fine. still have fuel mix running down the outside of the lower unit. I'm afraid the gasket you mentioned may very well be bad, that's going to mean pulling the power head, correct? that's not something I'm set up to do. I've found a guy not far away who says he's been in business for over 15 years, he might be getting some new business.

I plan on putting it in the water tomorrow to see if it will run in the water as well as it seems to on the muffs. Last time I tried that before the carb rebuild, it wouldn't. We'll see

 

[emdsapmgr]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

Pulling the powerhead is probably a 2-3 hour flatrated job. Not a big deal if you've got an engine hoist. That block is one that already has a lifting eye by the flywheel.

 

[papachaz]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

Hi emd, thanks again! i could rent an engine hoist, might even have a nephew who has one I could borrow. If I had to pull it, without looking it up, I'm thinking I could drop the lower unit, drop the lower cowling, access the bolts and raise it high enough to clean the surfaces and change the gaskets without having to pull everything else? Still probably not something I'd do on my own though. might not have to....

today I took it and put it in the lake. Started right up, no effects from the back pressure on the exhaust at all. Pushed out away from the trailer and idled over to the dock. I left it running at idle while I walked back over to the ramp and parked the truck. Got in, eased out of the no wake zone and hit it. Got up on plane smooth and easy, got it up to 4400 rpm pretty quick and smooth. ran it there about a minute and it bogged back to 3200 and wouldn't budge a bit back up. Being too close to the ramp at the creek entry, I idled it back past the ramp, and out onto the main part of the lake.

after getting past the no wake zone, I hit it again. it went up to 3200-3300 but just seemed not to have a lot of power at all. expected I know. So beginning to feel frustrated, I pulled it back and turned back to head back to the ramp. Hit it again, and it went back to 3200, ran there for less than a minute then caught back up and went back up to 4400. I stayed and played figure 8's on the big water for over an hour, never had another problem with it bogging, no hiccups, no coughing. And no leaking under the cowling. I don't know if it had picked up some trash in the fuel lines, or just needed to warm up good.

I did put new gas in with what little was left in the tank from last year, tho previous owner said he always kept seafoam in it. This weekend we're pulling the camper and the boat back to the lake, and there is a lakeside station with pure gas, I plan on filling it there and taking a couple extra cans to fill as well. We'll see how it runs with high test pure gas over the weekend, I may do a decarb on it with a gallon of gas loaded heavy with seafoam just to make sure the cylinders are clean. I have already put new plugs in it, so that's not a problem. Will post monday on how the weekend went! all the help and suggestions are much appreciated!

 

[papachaz]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

put it in the water over the weekend. Still had the issue of not wanting to go over 3200 rpm when cold. Once I ran a few minutes, it would catch up and run out at 4700. Seems the pure gas 91 octane ran a bit better, I got a few more rpm at WOT. Once it caught up.

also, I had ordered a new rectifier. It came in Friday and I got it put on. After running for 10 minutes or so, I saw the voltmeter go to 16. I realize it's going to charge the battery a bit, but is it normal for it to go that high? I do know that boat gauges are not always the most reliable. My speedo is stuck on 30 mph, and the gas gauge shows below empty when the tank is right at half full judging by sloshing it around.

 

[emdsapmgr]

Re: 1979 115 gas mix coming from the exhaust and under the cowling

A rectifier-regulated engine will regularly see 16+ volts on the voltmeter, once the engine has run for 15-20 minutes. That's normal. Your rpm drops indicate that it's possible your ignition may be malfunctioning. It may be dropping a cyl. (only running on 3 cyls). Once the engine is warmed up and it's losing rpm's, check for spark on all 4 cyls.