Mariner Marathon 135 1988 opinions

[powrguy]

I've got a 1988 Mariner 135, which I've had a couple questions posted before on.

Is this essentially the same as the Merc 150 2.0 of the same vintage?

Can I use rebuilt carbs (WH type) from a 150 without a bunch of changes (jets, etc.)?

I've ordered the gaskets to use when I take the carbs off and clean them up, to remedy a cold start/won't idle problem, and probably will be replacing the thermostats, too.

I've got the Mercury Manual for this engine, too, and hope I can do an at-home "link-and-sync" using the instructions there, but am thinking that I might also want to rebuild the old fuel pump as someone mentioned the diaghram usually turns to "bacon" from ethanol in today's fuels.

Any thoughts on this engine and whether I should start pumping $$$ into it?

I have thought of upgrading the engine (selling it and getting a 200HP), as that's what the max rating on my boat is, and maybe I'd be happier with a bigger motor.


thanks

 

[Faztbullet]

Re: Mariner Marathon 135 1988 opinions

Yes you can change carbs as long as they are not the same WH number then all you would have to change is the jets and keep your carbs. If I was going to do this I would find a set of WH-41 carbs from a Xr2/mag II engine and install the 200 divider plate for a little better breathing.

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Both the Merc 150 and the Mariner 150 are 2.0, as is this 135 HP Marathon, so I wondered what is the difference between the 150's and the 135's? Is it just the carbs/jetting, or is there more to it? Are the other accessory parts interchangeable (fuel pump, power packs, etc.?)?

 

[Faztbullet]

Re: Mariner Marathon 135 1988 opinions

That year model everythings the same except carbs as venturi's are smaller, thus lower hp...everything else will interchange.

 

[lprizman]

Re: Mariner Marathon 135 1988 opinions

how many hours?
what is the compression in the cylinders?
what are you putting it on?

this info would help

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Don't know the hours. It's on a Robalo R2020 center console. Compression is 110 across, within +/- 2 psi. Generally, this engine was used in fresh water, except for the last two years. Well taken care of, too, it appears.

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Forgot to mention that it still has the VRO working, never converted to straight pre-mix.

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

That year model everythings the same except carbs as venturi's are smaller, thus lower hp...everything else will interchange.

With the replacement of the carb's (the original 135 Marathon with Merc XR-2 carbs), would some other modification be required, such as divider plate and/or ignition timing, etc.?

 

[Dukedog]

Re: Mariner Marathon 135 1988 opinions

Most everything is tha same. Lose tha oil injection mainly cause of age.

You shouldn't need ta change nothing. Jettin' in a peticular carb is just what it is. Its for that carb no mater what motor its on. Now if you use a carb thats not called for on a peticular motor ya gonna have ta jet it tha old fashioned way by reading tha plugs (mostly mains, idle to your likein'). Tha jettin' and carbs are motor matched from tha factory. Use factory jettin' for tha carb as a base line then go from there. JMO.......................

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Most everything is tha same. Lose tha oil injection mainly cause of age.

You shouldn't need ta change nothing. Jettin' in a peticular carb is just what it is. Its for that carb no mater what motor its on. Now if you use a carb thats not called for on a peticular motor ya gonna have ta jet it tha old fashioned way by reading tha plugs (mostly mains, idle to your likein'). Tha jettin' and carbs are motor matched from tha factory. Use factory jettin' for tha carb as a base line then go from there. JMO.......................

Thanks for a great simple explanation. I found some XR-4 (not XR-2) carb's from a 150 Merc, and hoped to clean 'em up, re-gasket them, and then swap them out onto the 135 Mariner, and see what happens. I am pretty sure the cold idling problems are just due to carb gunking, and carbon in the engine. I plan to do the carb's as a winter project, along with cleaning up and re-painting the engine.

 

[j_martin]

Re: Mariner Marathon 135 1988 opinions

Thanks for a great simple explanation. I found some XR-4 (not XR-2) carb's from a 150 Merc, and hoped to clean 'em up, re-gasket them, and then swap them out onto the 135 Mariner, and see what happens. I am pretty sure the cold idling problems are just due to carb gunking, and carbon in the engine. I plan to do the carb's as a winter project, along with cleaning up and re-painting the engine.

With good compression, anything else can be fixed fairly easily on this engine.

When the carbs are off, you might as well peel another layer and pull the reed block and check it out.

Carbs, reeds, and bleed system all have a big effect on idle.

An XR4 is a 2.4. (I think uses WH41 carbs) I think the carb bores are bigger, and that could mess with your idle and hole shot. You might be better off just putting the stock carbs into proper shape.

hope it helps
John

 

[Dukedog]

Re: Mariner Marathon 135 1988 opinions

One other thing 'bout Merc carbs. They are known ta be a touch (idle and mains) on tha fat side in most (production WH series V6) cases from Merc. Which is probably a good thing in a production motor

Just a thought for ya. In your case just tha 200 tuner might benefit you a little but keep your adapter plate. It has tha bigger exhaust holes where tha 200 adapter plate has smaller exhaust holes. Tha 2.0 block like yours has tha big exhaust. Good luck with it..............D

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

"just a 200 tuner"

What the heck is a "200 tuner" ?????

 

[Dukedog]

Re: Mariner Marathon 135 1988 opinions

I have thought of upgrading the engine (selling it and getting a 200HP), as that's what the max rating on my boat is, and maybe I'd be happier with a bigger motor.


thanks

Its same as a car motor header. Probably doesn't mater cause it doesn't sound like your going that far. Ya gotta pull tha powerhead and adapter plate ta get to it. A little more involved. Dought it would be much of an improvement anyway without doin' a whole bunch more stuff to your motor.
Just from tha way your coming across I would suggest ya rebuild tha stock carbs. Get tha motor running good, sell it and get tha 200. Without doing some extensive work you really won't see much improvement. JMO, which with 2 bucks (won't be long) will get ya a small cup a coffee...............D

PS, you would be A LOT happier.

 

[sschefer]

Re: Mariner Marathon 135 1988 opinions

Go ahead and go with the 150 carbs. You don't need to change anything else if you don't want to. Do a crankcase pressure test as per the service manual to find out if you need to replace reeds. 110 lbs of compression is excellent for that engine.

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Go ahead and go with the 150 carbs. You don't need to change anything else if you don't want to. Do a crankcase pressure test as per the service manual to find out if you need to replace reeds. 110 lbs of compression is excellent for that engine.

Well, it's gonna be one of two things:

I'm pulling the original carbs, lookin' them over real good, soaking 'em clean, then re-installing them if I find they're really cruddied-up.

Or:

If the carbs look pretty good, I may just check out the reeds (the crankcase pressure test), and also the bleeder system that may be causing cold/idle issues.

Finally, if it's running okay after the cleaned carbs, I'm done. I plan also on doing a good seafoam treatment in the spring, I'm rebuilding the fuel pump this winter, and of course new plugs after that. I think the carb's are just crudded up, myself, and the engine needs a good de-carbon treatment, too. Fuel filters also will all be changed.

I am leaning toward keeping my original carbs, and like what was mentioned previously, keeping my eye out for a carb 200 Merc.

thanks

 

[sschefer]

Re: Mariner Marathon 135 1988 opinions

Sounds like a good plan. I just snagged a set of 150 carbs of eBay for 99.00. I'm puttibg those on my 135 next week. My engine is freshly built and slightly modified so it should do well with a little more air and juice. I'm already getting the performance that a new 150 optimax gets according to Merc so it would be fun to blow one away at the lake.

If you're going for a different engine I highly recommend you look for a 200 EFI (not optimax) and stay away from the DFI's there's too much to go wrong. The 200 EFI's have a big following and there's lots of fun stuff you can do to them. There's nothing wrong with carbed engines but the EFI's have more possibilites in my mind.

 

[powrguy]

Re: Mariner Marathon 135 1988 opinions

Sounds like a good plan. I just snagged a set of 150 carbs of eBay for 99.00. I'm puttibg those on my 135 next week. My engine is freshly built and slightly modified so it should do well with a little more air and juice. I'm already getting the performance that a new 150 optimax gets according to Merc so it would be fun to blow one away at the lake.

If you're going for a different engine I highly recommend you look for a 200 EFI (not optimax) and stay away from the DFI's there's too much to go wrong. The 200 EFI's have a big following and there's lots of fun stuff you can do to them. There's nothing wrong with carbed engines but the EFI's have more possibilites in my mind.

I see 150 carb's on Ebay all the time, from 150 Merc's. I thought about picking up a set and cleaning them up, rather than "unwrap" the 135 I have winterized and covered right now, and then installing them on my 135. That's what got me started on changing them out (to avoid having to pull my motor, as it's all covered, wrapped, etc., and easier to wait until Spring to work on it). My boat is rated for 200hp, though, and I am not looking for making it a performance outfit, just making it reliable and reasonably powered. I thought the carb/idling issue might be an opportunity to give it a liitle more power, and that's what got me onto the carb swap idea/discussion. I also think the carbon and fuel pump work will go a long way toward restoring the motor to its original power and idle issue, too. The Robalo R2020 I have weighs in at about 2200 pounds, dry, so it's a load.


thanks