My Mariner 60 is tempermental

[Pool Guy]

Hello from Wisconsin.

I recently purchase a 1988 Mariner 60 (08399561 or 0B399561?). Some days it runs great, but most days it can be a little hard to start and idle poorly. When this happens, the motor seems to have very little power. When you throttle up, the motor just boggs down. I have to run it at low RPM for maybe 5-10 or more minutes. Then all of a sudden, like someone threw a switch, bam! Full power and it's running great for the rest of the day.

Does this sound like an ignition problem? Where do I start?

Compression and plugs look OK.

I read duck0872's similar post from this morning (Mariner 60 cylinder #3), and I'm speculating we may have similar problems. Brain box? Stator?

Pool Guy

 

[duck0872]

Re: My Mariner 60 is tempermental

I'd check the fuel system first. Could be a clog, the carbs could be the issue too. There could also be a leak in the fuel pump diaphragm or bad pump check valve. Get a friend out with you and squeeze the primer bulb while it's bogging down to see if the motor revs up. I checked all this stuff before I moved on to the ignition system. And I'm glad I did because I found the fuel pump had a leaking diaphragm and the tank fittings were sucking some air. While trying to figure out what's up with my 60 I read in a few places that fuel problems tend to be more common than ignition problems, but you never know if they're right. If the motor has good compression on the cylinders then it's either spark or gas, and I find the fuel system much easier to check on your own than the ignition. Good luck and hope we're both back up and running soon.

 

[Pool Guy]

Re: My Mariner 60 is tempermental

Thanks for the reply duck0872. The reason I was leaning towards ignition system is the fact that after 'warming up', she runs like a champ. I would not expect a fuel system problem to suddenly clear up after a good warmup, but I can understand how an electrical problem could be intermittent in this way.

That said, I am going to give the fuel system a once-over and try the primer bulb trick.

Pool Guy

 

[sschefer]

Re: My Mariner 60 is tempermental

From what several mechanics have told me and from my own experience, these engine years are notriously cold blooded.

You can improve things by making sure that the choke solenoid is working properly and that your timing is correctly set.

I don't know if you're using the permanent gap style plugs or not but if you are, changing to a gapable plug will help on older models. New, fresh, correctly gapped plugs won't seem to make a huge difference at first but they, in my case at least, seem to last longer before fouling.

Most of the problem seems to stem from the quality of fuel that we get today. In 1988 a higher octane fuel was used to determine things like jet size, air/fuel ratios, etc. If you run premium grade fuel and correct proportions of octane boost it may help.

Reducing the Max Advance to no more than 21 degrees is often recommended also.

Your baseline idle is set during the link and synch procedure. Followed by carb adjustment and finally initial timing. Slight adjustments to initial timing can improve the idle but an improvement in smoothness often leads to increased idle RPM. If you go too high then you risk damage to the lower unit when shifting. Anything above 800 RPM in neutral is usually considered too high. You'll need to check but I believe 650 RPM at idle in gear and most importantly, in the water is correct.

I wish you all the luck in finding the sweat spot.

 

[Pool Guy]

Re: My Mariner 60 is tempermental

Thanks for the reply sschefer!

The symptom that keeps leading me back to ignition problems is the way my outboard can go from running poorly to running perfect like someone throwing a switch. I'll be tooling along at WOT, but power is poor, then I am almost knocked out of my seat when she suddenly kicks in and runs great for the rest of the day. If it were fuel mix related or timing related, woulden't it run poorly all the time? I supose the choke solinoid could be suddenly releasing the choke. Could I be running on two cylinders until it decides to take off and go?

Pool Guy

 

[westexasrepublic]

Re: My Mariner 60 is tempermental

My problem is so similar I started reading and thought I started this thread.

FYI - I replaced, stator, trigger, wiring harness, rectifier and spark plugs.

I thought since I had the notorious merc wire rot that it would remedy the problem. now all my electrical looks new, but my engine (79' Mariner 70hp 3 cyl) still fires good, idles good, goes to full throttle, bog bog bog......more bogging. then it kinda burps like one of the other cylinders starts firing and BOOM im up on plane like nothing was ever wrong.

so I checked the coils, they are good, but now Im gonna replace my plug wires, and the switchbox, which is what I think the problem is all along, is bad switchbox. if you replace yours before me, let me know if that remedies the problem. cuz nothing has so far.

 

[sschefer]

Re: My Mariner 60 is tempermental

Well, I don't know, I've got a new switch box on mine and it didn't help. Heck I rebuilt mine from the bottom up twice now and I still have the same exact problem as when I started. The only thing I haven't replaced is the carbs but they've been completely rebuilt.

Please don't follow me on my fools errand here but mine being a 100hp 2+2 I'm begining to think that the problem is the factory set air mixture on the carbs and the lousy fuel we have today. I think the plugs are fouling until we get enough heat going on to keep them clear enough to fire.

It's only a matter of time before California say's I can't run this 2 stroke carbed engine anyway so mines headed for the bone yard this winter. I can't sell it the way it is, I'd just get it back so I'm parting it out. Most of the parts are hard to find used and NLA new.
This thing of mine really has me beat.

 

[westexasrepublic]

Re: My Mariner 60 is tempermental

liberal cali law makers, BLAH!

so Pool guy any word? you started this thread. I think my spark plug wires come in today.

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

I had exact same problem. found out it was switch box .shop could not fix it kept charging me money to do fuel fixes carbs then fuel pump then readjust carbs. gave up on them called my brother he is auto mechanic. he said sounds like ignition was breaking down. would do it like you said when ever it felt like it. what was happening was when it was acting up it was only running on two of the three cylnders. big loss of full throtle. My brother ran some tests with a meter when we knew it was having one of its fits. Thats how he found it but, I am not sure of the test someone with the know how here could guide you ask about switchbox test. drove me crazy til it was fixed because you never knew when it would act up. mine is 1994 mariner 50 hp 3cylinder 2 stroke

I feel your pain it sucks I was going broke with the shop charging me 100.00 an hour 3 times I had it in there. my brother was pissed when I told him What was going on. He lives 100 plus miles from me and is busy so i didnt want to bother him. he came right down and fixed it up for me. Two years now trouble free. good luck guys hope its all good for everyone soon. PS. I always run premium Fuel and when possible try to get it from same place.my brother said becareful where you buy because if the station is realy high on their prem they probably dont sell alot of it and you dont know howw long it sits in tank and better chance for it to take on water or become old.And these motors like good clean fuel they are touchier than cars.

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

Hey SSCHEFER saw your rebuild post coppied your hose trick for the cables in the pan great idea thanks for the tip and good luck with you motor mine is not cold blooded at all finaly got it humming good after a nightmare with shop good luck man dont give up on her

http://stumpmj.spaces.live.com Pics of my boat check out the 7.68 lb OHIO largemouth WOW!

 

[westexasrepublic]

Re: My Mariner 60 is tempermental

My last replacement will eventually be the switch box. Once I replace that, I will have eventually replaced all the electrical.

 

[Pool Guy]

Re: My Mariner 60 is tempermental

Hey westexasrepublic, thanks for the post. I don't feel so alone any more! I believe we have the same problem. My boat and motor spent most of it's life in Texas before it decided to move up here to Wisconsin. Maybe Mariners get tempermental living in Texas

OnTheWaterNow, thanks also for your reply. I am seeing a switchbox in my future.

I have been reluctent to stick money into my motor until I have some confidence that whatever parts I buy have a decent chance of solving the problem. Westexasrepublic, do you want to try the switchbox fix first and let me know? Otherwise I'll order one up and let you know my results. I'm getting sick of bogging my way to my favorite bass slough here on the Mississippi river and need to try something.

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

Correct just because it fixed mine Im not saying it will fix yours I just trusted my brother and he did test it before we bought one

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

poolguy did you see the sweet basss my brother caught

 

[westexasrepublic]

Re: My Mariner 60 is tempermental

well im sure im gonna end up getting one, but not for a little while...im gonna get my timing right first, then get the switchbox. but curious, what brand are you getting? sierra, CDI, quicksilver? just FYI if you have an Oreilly Auto, you can order all your parts from Sierra for cheap and pay no shipping, also if its not the part you need they just keep it. I bring that up since they order the plug wires for my boat and they where not long enough. so Im gonna try a DIY kit that Sierra offers.

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

I got quicksilver 3327778a12 not sure if it is same number you would need

 

[OnTheWaterNow]

Re: My Mariner 60 is tempermental

If you guys havent tested the switchbox and arent shure how to I will call my brother and see if he wiil detail how he did it and e-mail it to me he had a meter of some kind and a heat gun he would heat the switch box up look at some numbers cool it down look at some numbers I was completely lost Ill see what i can come up with for you

 

[Silvertip]

Re: My Mariner 60 is tempermental

When the engine begins to bog, immediately shut down. Don't let it idle. Even if you are in the middle of the lake, shut it down. Since this will be a troubleshooting process, run the engine without the cover and make sure you have a plug wrench and new plugs along. Now then, with the engine off, climb overboard, remove the plugs and inspect them. A cylinder that is not firing will display that fact on the plug. A plug that is fouled with carbon deposits or fuel soaked indicates too much fuel or lack of spark is the issue but at least you can now identify the cylinder. A plug that is bone dry can have all the spark in the world but if it lacks fuel the plug will stay like new.

If you elect to switch from a surface gap plug to a standard plug, be darned certain you understand what you are about to do. Improper heat range can destroy an engine and you have no cross reference so some research is required. And after you make the switch, don't just hammer down and forget about the change. You need to make several test runs working up to full throttle along with several plug reads to make sure you have the correct heat range.

 

[westexasrepublic]

Re: My Mariner 60 is tempermental

in my manual there is a test for everything BUT the switchbox, which is the only thing I dont know how to test.

 

[Pool Guy]

Re: My Mariner 60 is tempermental

OnTheWaterNow- Did your brother do this test while on the water? Or with one of those garden hose things? Since he used a heat gun, I suspect it was done out of the water? That gives me an idea... if it is the switchbox and it is thermal sensitive, only firing two cylinders when cold and kicking in all three cylinders once warmed up, then a heat gun and some freeze mist alternately directed at the switch box might be an appropriate troublshooting idea. I have the heat gun, and a can of freeze mist is cheaper that an experimental switchbox.

And no, I did not see your brother's bass. Were is he picture?

Personally I have no plans on switching to gapped plugs. I just want my motor to behave consistently, warm and cold.