1986 Cajun w/ Johnson 150 GT (V6)

[TWO21]

New member here that has been trolling the forums for the past couple months. Just started on this project after my uncle didn't want anything to do with this boat, so it sat around at my parents lake house for 20 years. Last tag on it was from '96. Started a thread in the restoration section to show my progress with this project but wanted to put this here for engine issues I've had.

What I've done so far:
Cleaned and rebuilt all 3 carbs, new water pump, replaced some fuel lines and primer bulb, drained and cleaned the gas tank, cleaned fuel filter, new spark plugs, fresh oil. I got it running a couple weeks ago just on muffs and it was circulating water, had a good stream going after unclogging the line.

Problem I ran into:
This weekend the warning horn was screaming at me before ever starting it up. Had the key in "on" position and the horn was a continuous beep and it's driving me crazy. I turned it off, which may have reset it because it didn't come back on until after I started it up and had it idling for about 20 seconds. The continuous beep is either overheat or fuel restriction. Engine didn't feel hot but it smoked quite a bit (running rich?) and even had a little smoke from the exhaust after I turned it off. I'm thinking vacuum leak in the fuel system because when I pump the bulb, it never becomes firm. I can watch fuel pour into the fuel filter as I prime the bulb but it drains out after 5-10 seconds. Someone else put in the new fuel lines and bulb, so I haven't had time to double check that the arrow is facing the correct direction.

Next Steps:
Putting in a new fuel filter, cleaning or replacing anti-siphon valve (if it has one, not sure if they were required in '86), checking vent tube on the tank, cleaning the pulse limiter/flame arrestor, and double checking my fuel hoses (most have been replaced). I also bought the rebuild kit for the fuel side of the VRO, thinking this needs to be done anyways to replace the diaphragm. Am I crazy to think the warning is a fuel restriction? Vacuum switch is shorting out? Maybe temp sensor is corroded?

 

[emdsapmgr]

You can do a simple test. Disconnect one of the two wires going to a head temp sensor. Run the engine. See if you get a horn. Then disconnect the one to the other head. Run the engine and see if you get a horn. Then disconnect the fuel vacuum sensor. Run the engine and see if you get a horn. The fuel line fuel filter is only full when you prime the hose bulb. Not while normally running. Fuel hose bulbs are not all the same. Bombardier factory ones are best. It is possible that one of the ball valves inside the primer bulb is bad. Also, make sure the fuel hose bulb is oriented generally upward. The arrow should be pointing in an upward direction. If it's laying downhill in the splashwell of the boat, it can malfunction internally if it's old, worn.

 

[TWO21]

No Title

You can do a simple test. Disconnect one of the two wires going to a head temp sensor. Run the engine. See if you get a horn. Then disconnect the one to the other head. Run the engine and see if you get a horn. Then disconnect the fuel vacuum sensor. Run the engine and see if you get a horn. The fuel line fuel filter is only full when you prime the hose bulb. Not while normally running. Fuel hose bulbs are not all the same. Bombardier factory ones are best. It is possible that one of the ball valves inside the primer bulb is bad. Also, make sure the fuel hose bulb is oriented generally upward. The arrow should be pointing in an upward direction. If it's laying downhill in the splashwell of the boat, it can malfunction internally if it's old, worn.

Perfect, I will try this once I'm at the lake this weekend! When I prime the bulb, is the fuel supposed to stay in the filter before starting the engine? Just to be clear, it's the spin on clear filter (#5 in pic) at the rear passenger side of the motor.

 

[James R]

I think there is a fuel pressure sensor on your motor. On the port side and tees into the fuel line. If there is not enough flow and therefore pressure it will sound off. Did you use 3/8 hose, fittings and bulb when you refitted.

 

[TWO21]

I think there is a fuel pressure sensor on your motor. On the port side and tees into the fuel line. If there is not enough flow and therefore pressure it will sound off. Did you use 3/8 hose, fittings and bulb when you refitted.

#10 in that picture is the pressure switch, which is in question. Going to try instructions from emdsapmgr but seems strange that the fuel system doesn't appear to hold pressure.

 

[emdsapmgr]

The fuel filter is the top half of #5 in the picture. It is sold separately (you don't have to buy the bottom). It does not come with the two orings, so make sure you get them from the dealer when you get the filter. Actually #10 is a vacuum switch. It activates when the fuel pump tries to suck fuel, but there is a restriction. This vacuum switch notifies you of high vacuum. (sort of like warning you when a plastic fuel tank vent is closed and the pump is trying to suck so much fuel that it could collapse a plastic fuel tank.

 

[TWO21]

Update:
Put in a new fuel filter, parts 5, 6 & 7 from the previous catalog photo. Replaced hose 23 because it was cracked. Used a fuel piston kit to replace the fuel side of the VRO pump. Checked the anti siphon valve and it is functioning properly. Cleaned the flame arrestor/pulse limiter while I had the VRO pump out. Put the boat in the water this time instead of using muffs and the alarm went away and never came back (small victory!). Adjusted the idle so it was running a little better but still has the issue of dying when throttling up. It happens on muffs and in the water, it just takes longer to die out on muffs because there's no load on it. Tried pumping the bulb while throttling up but didn't seem to help. Any ideas? I did notice that on the VRO, the plastic connection where fuel/oil line goes on seems shorter than normal. Made it difficult to connect and tighten the hose down.

 

[James R]

Take a look at the primer solenoid. It is possible that it is stuck open or leaking. Not uncommon, This would account for the bulb not hardening, the rich mixture causing smoke and the lousy running and possibly the vacuum switch triggering. Simple way to test. Carefully remove one of the primer feed lines to a carb and try turning the engine over. If fuel pours out without your activating the primer you have found a problem. Of course the little red lever on the solenoid should be inline with the solenoid body or effectively the valve will be wide open anyway.

 

[TWO21]

Take a look at the primer solenoid. It is possible that it is stuck open or leaking. Not uncommon, This would account for the bulb not hardening, the rich mixture causing smoke and the lousy running and possibly the vacuum switch triggering. Simple way to test. Carefully remove one of the primer feed lines to a carb and try turning the engine over. If fuel pours out without your activating the primer you have found a problem. Of course the little red lever on the solenoid should be inline with the solenoid body or effectively the valve will be wide open anyway.

You might be on to something...is that primer solenoid only for choke or does it also affect operating conditions as well? Just thinking back to starting it last weekend, it didn't seem like the "key in" choke was doing much. The manual says you can press the key in to choke it and the engine speed should drop 1000 RPM, which I don't remember that happening.

 

[TWO21]

No Title

...Tried pumping the bulb while throttling up but didn't seem to help.

This got me thinking that it may not be a fuel issue and possibly an air or spark problem instead. When advancing the throttle, I pumped the bulb as the engine sounded like it was starting to die but didn't save it. Assuming it's a fuel problem, that should save it from dying right? I read some other posts about the pulse limiter helps control the crankcase vacuum and the air side of the VRO. I cleaned this part when I had the VRO out (replacing fuel side internals) but could it be restricting air flow at higher rpms? The photo shows the flame arrestor that I cleaned but is that also the pulse limiter? The newer pulse limiters don't look anything like that.

 

[James R]

Systematic Fault finding is the name of the game so before you take off in a totally different direction check the things that have been suggested. You have started on fuel now finish the fuel side and eliminate that. If the primer sol is leaking or stuck open it will certainly affect the running at any speed.

 

[emdsapmgr]

Possible that the engine is running lean at transition. Maybe the mid-jets have debris in one or more of them. That would cause a bog before you get into the higher speeds.

 

[James R]

EMD,,, you could be right. When a motor comes to me and the owner says "I have cleaned the carbs" I take em down anyway and do a proper job.

 

[TWO21]

I haven't had much time to troubleshoot and it's been ridiculously hot. Hoping to have time this weekend. James, when you say "proper job" what do you mean? I took the carbs out, took them completely apart, sprayed carb cleaner to clean them up, blew them out with compressed air, put them back together with a rebuild kit. The only thing I didn't do, and this may be a big issue but didn't really know what I was doing, was punch out the caps and replace them. My kit also didn't have replacement jets for the really small ones, inside the top part of the carb. I obviously don't know which are high speed jets and which are low.

 

[TWO21]

No Title

Didn't punch out plugs (#2), didn't mess with the lead shots (#9), didn't replace orifice plugs but cleaned them (#3,4,5). Used the OEM rebuild kit and followed the manual minus punching through and replacing the core plugs. Should I take them back out and do those?

 

[TWO21]

Tried the test on the primer solenoid and didn't have any fuel come out of the hoses. I noticed that I hear a click when I push the key in to choke, I'm assuming that's the solenoid activating.

Side note, I replaced the fuel line going from the tank to under cowl connection (finally!). The hose was in terrible shape, so that could be part of the problem. Started the engine on muffs today, seemed to idle fine and run in forward neutral fine. Only tried giving it a little throttle twice: first time it died, second time it ran for 3-5 seconds before I shut it down. Didn't want to chance more throttle on muffs, so I'll be taking it to the lake in a week to try again.

 

[TWO21]

No Title

Top part of the hose where it connects to go from under cowl to topside of the boat.

 

[Bosunsmate]

Id run it for longer and check the heads dont get too hot so you know the thermostats are working.
You dont need to increase revs to check this

 

[oldboat1]

just my two cents -- When did uncle last replace the water pump? Can't tell a lot running on muffs, as the hose pressure partially takes over for what the impeller would do in the lake. Maybe you have replaced it.

Your carb cleaning technique sounds right to me. I'm not hands-on familiar with your carbs. Usually expansion plugs provide access to idle passages, so it makes sense to just pull and replace them when doing the carbs. A small blockage can give shifting stalls, rough idling, etc. etc. For jets, I'm a big believer in soaking carb halves (whatever is metal), then blowing out with carb spray, also some picking with a piece of mono or soft wire, jets aside. And best to leave the jets in place to avoid damaging them (just soak and spray).

 

[TWO21]

Id run it for longer and check the heads dont get too hot so you know the thermostats are working.
You dont need to increase revs to check this

I was thinking about replacing the T-stats but wasn't sure how far to go with the parts. Once I get in there to replace both T-stats, I'll need new gaskets but then there's also retaining washers, pressure seals, grommets, etc. When I have it in the water, not on muffs, it has a good stream and I don't get any buzzer going off.

just my two cents -- When did uncle last replace the water pump? Can't tell a lot running on muffs, as the hose pressure partially takes over for what the impeller would do in the lake. Maybe you have replaced it.

Your carb cleaning technique sounds right to me. I'm not hands-on familiar with your carbs. Usually expansion plugs provide access to idle passages, so it makes sense to just pull and replace them when doing the carbs. A small blockage can give shifting stalls, rough idling, etc. etc. For jets, I'm a big believer in soaking carb halves (whatever is metal), then blowing out with carb spray, also some picking with a piece of mono or soft wire, jets aside. And best to leave the jets in place to avoid damaging them (just soak and spray).

I replaced the impeller along with cleaning and rebuilding the carbs before starting it up. Didn't punch out the Welch plugs because some people say don't mess with them unless they're scratched or have a hole in them. I didn't soak the carbs because they looked fairly clean and when I sprayed them with carb cleaner, I made sure to spray where all of the brass jets are.