1988 Mariner Marathon 135

[powrguy]

I've got a 135HP Mariner O/B, V-6, that is really cold-blooded. It needs about 10 full minutes to warm up, before you can put it in gear without stalling.

My intent is to give it the Seafoam treatment, to clear out carbon, then also change fuel and water separator filters, and see what happens. Beyond that, my question is in regards to removal and disassembly, soaking, and reassembling and installing the carbureators.

I have worked on auto engines, all the way to full rebuilds, etc., but am not as comfortable on outboard engines.

However, my question is how do I adjust and "syncronize" those three dual throat carbs, or can I just be careful not to disturb the linkages, and hope for the best? I don't understand how I can be sure I have all cylinders optimally mixed, and don't want to lean out a cylinder and fry it by screwing it up.

thanks

 

[j_martin]

Re: 1988 Mariner Marathon 135

I've got a 135HP Mariner O/B, V-6, that is really cold-blooded. It needs about 10 full minutes to warm up, before you can put it in gear without stalling.

My intent is to give it the Seafoam treatment, to clear out carbon, then also change fuel and water separator filters, and see what happens. Beyond that, my question is in regards to removal and disassembly, soaking, and reassembling and installing the carbureators.

I have worked on auto engines, all the way to full rebuilds, etc., but am not as comfortable on outboard engines.

However, my question is how do I adjust and "syncronize" those three dual throat carbs, or can I just be careful not to disturb the linkages, and hope for the best? I don't understand how I can be sure I have all cylinders optimally mixed, and don't want to lean out a cylinder and fry it by screwing it up.

thanks

These engines are about 1/4 as complicated as an automotive engine. Get a manufacturer's maintenance manual, and in that manual is a complete linkage adjustment and timing procedure. It's really not very hard, and will set it up right for you.

There's also setup information, like correct jets in the carbs, etc. It sounds like you might be a little lean at idle, assuming the t-stats are OK and it is warming up. The telltale stream should start within one minute, and be lukewarm.

hope it helps
John

 

[powrguy]

Re: 1988 Mariner Marathon 135

Thanks, John.

Actually, it take a LITTLE longer than a minute for the telltale to start flowing, but once it does, it's strong and steady. I can tell when the t-stats open, as that's when it flows.

The engine doesn't look overly complicated, and I was finally able to locate the Mercury Service Manual for my particular motor, and will probably go through reading it a few times on the carb cleaning/settings/link+sync procedures. I also probably will be changing some of the fuel lines on the engine, as they look like they are possibly a little dried out.

Would I be better off to Seafoam-treat the engine BEFORE I rebuild the carbs, or afterward to de-carbon?


thanks

 

[sschefer]

Re: 1988 Mariner Marathon 135

If what John has said doesn't fix the problem, (and it probably will), then you might want to check the poppet valve. If the diaphram is torn or it's stuck open it can make a difference in warm up. The poppet valve is located on the port side of the block at the bottom near #5 cylinder. It should have a 90 deg fitting on it with a 5/16" hose going up to the top of the block. It sort of works like a thermostat except it opens with pressure and not temp.

Just a FYI the pee stream does not indicate that the thermostats are opening it just means that the block is full of water and there is some pressure. If it was mine I'd pull the thermostats and test them. I think yours are 143 degree T-stats unless it's a high altitude motor and then they might be around 120. Check the service manual.

 

[powrguy]

Re: 1988 Mariner Marathon 135

Thanks. I planned on replacing both thermostats in the Spring, and I'll probably replace the poppet valve then, too.

Living in the North country, where boating season lasts 8 months (at MOST), it makes for a long off-season to get ready for Spring again.

 

[powrguy]

Re: 1988 Mariner Marathon 135

These engines are about 1/4 as complicated as an automotive engine. Get a manufacturer's maintenance manual, and in that manual is a complete linkage adjustment and timing procedure. It's really not very hard, and will set it up right for you.

There's also setup information, like correct jets in the carbs, etc. It sounds like you might be a little lean at idle, assuming the t-stats are OK and it is warming up. The telltale stream should start within one minute, and be lukewarm.

hope it helps
John

Can you tell me what the difference between this Mariner Marathon 135 (I know it's a 2.0) and a Mercury 135 of the same vintage is, other than paint color and decals? This motor was the motor packaged with the boat (a 1988 Robalo R2020), and I assume it was set up correctly (jets, etc.), but I sometimes find Mercury 135HP parts listed, with no mention of Mariner.

 

[Dukedog]

Re: 1988 Mariner Marathon 135

Nothing different. Tha only part numbers that differ from Merc are tha PAINTED pieces................

 

[j_martin]

Re: 1988 Mariner Marathon 135

All of the water for the pee stream goes through the thermostats, so yes, the pee stream is an indication of the t-stats opening. If it pees before the t-stats open, the gaskets are bad or mis-installed. Feel it, it should be warm.

A motor is matched to the boat by the prop and setup. Jets are adjusted for altitude, and lately maybe fuel, especially if it goes to 15% ethanol.

That engine was built before the ethanol nonsense hit, so many of the rubber parts, including hoses are not compatible. If the hoses look old, I'd replace all of them. I definitely would NOT run SeaFoam through that old rubber. All it will do is finish the damage and really mess things up.

If the fuel pump has old parts in it, they are probably damaged. The new check valves are a clear plastic. Rubber check valve life expectancy is measured in days, maybe hours with modern fuel. They turn into bacon.

As the motor is new to you, it would be a good idea to do a compression test on it, just to make sure the problem isn't that it is just plain worn out.

When you take the carbs off, check the numbers compared to what should be there. If it isn't in your book, post them here. Somebody will look them up for you. If some poorly educated "mechanic" put the wrong carbs on and put the jets in for the right carbs, it could be real trouble. Jetting is mostly determined by the carb model, and a little by application and altitude. All the carbs look alike, but they're cheesed out different inside.

If it were mine, I'd get a reed plate gasket when I got the carb stuff, and pull the plate off to check the reeds. It's not hard to do at that point. That's also a good time to check the bleed line check valves. They affect idle a lot.

hope it helps
John

 

[sschefer]

Re: 1988 Mariner Marathon 135

All of the water for the pee stream goes through the thermostats, so yes, the pee stream is an indication of the t-stats opening. If it pees before the t-stats open, the gaskets are bad or mis-installed. Feel it, it should be warm.

John is absolutely correct. For some dumb reason I read Mariner and thought of my 100.. Totally different animal. Your pee streams is on the exit side after the thermostats open just like John says. I appologize for the misinformation.

 

[Dukedog]

Re: 1988 Mariner Marathon 135

Your not completly wrong. They have a small "bypass" hole or slot that will let a small amount of water pass before they open. So that doesn't mean a bad gasket.......only if its on tha outside of tha housing.

 

[sschefer]

Re: 1988 Mariner Marathon 135

Your not completly wrong. They have a small "bypass" hole or slot that will let a small amount of water pass before they open. So that doesn't mean a bad gasket.......only if its on tha outside of tha housing.

I ran my 90 2.0L v-135 for the first time today and had water out the tube in a couple of seconds. Had 143 degree water out the tube as soon as the thermostats opened, (3-5 minutes on the hose). Made a cup of instant coffee... hose water tastes bad...