Hello everyone, first post here! I apologize but it will be a long one as I try and explain my situation!

I've been a kayak angler for several years and just recently purchased a bass boat for a little more room. I picked up a 1997 Fisher F18 (made by Tracker boats) with a Mariner Magnum 3 outboard engine, the 150HP unit, allegedly the same engine as the Mercury XR6, just different cowling. This is my first full size boat and outboard motor.

I've heard from a couple of different people that the Mariner Magnum 3 / Mercury XR6 is an excellent engine, but that older carbureted outboards like this are cold natured, and they will sometimes take a couple of attempts to get started.

COLD START

I will perform this sequence to get her going:

- Prime the bulb
- Trim the engine down to level
- Advance the throttle 2/3 in throttle only mode
- Flip the ignition to ON, press and hold the choke
- While continuing to hold the choke, crank to the start position

Within about 1-3 cranks, the engine will fire up. After this I usually need to let her run at a higher idle (1000-1500 RPM) for a little before I drop the throttle to put her in gear or she'll die.

I have actually done this cold start enough now (once at the lake, dozens of times on the hose / muffs) to be comfortable with it. I just want to know if 1-3 initial cranks followed by a brief warmup period is expected behavior out of this engine or if something sounds like it needs to be cleaned or replaced?


Now here's the problem I am less comfortable with:

WARM STARTS

If after I get her going and travel to a spot on the lake, I cut the engine off then immediately back on, she fires right up perfectly on one key crank.

If I fish for 30 minutes though, come back to the ignition, I find it takes 2-4 attempts at cranking it to start. Sometimes I turn the key and hear nothing happening back there. Eventually I turn the key with the throttle up and I'll get a burp like it was about to crank up then usually more throttle and it'll crank right up.

The problem is it seems, that the more times I stop and fish, or the longer I take while fishing in between starts, the harder it gets to start it.

NOTE: On these "warm" starts while I'm on the lake, I never touch the choke - I did once and think I flooded it because I was getting burps from the engine as if it wanted to start, and choking it killed the burps. I eventually decided leaving the choke out of the "warm" starts and just using throttle-only mode advanced forward to start it.

Is it possible that the "choke-flooding" was an isolated incident and after 30-45 minutes, my engine completely cools down to the point where it needs a cold-start like choking?

I love this boat and the engine when we get going, I am just a little confused. I know carbureted engines all have their tricks, seems like outboards are no exceptions. I just want to gain a bit of confidence in knowing that my engine is in good shape and will start every single time.

To it's credit, it has never once NOT started on me or left me stranded. But I feel like hard starts are only a short way away from NON starts.

What do you guys think? (Sorry for the huge post!)

Thanks,
Dustin

All outboards are different having to learn their idiosyncrasies. If it ain`t broke don`t try tp fix it.

My Black Max 150 is basically the same motor, just a bit older. Your cold start is exactly how I start mine.

On warm starts I never advance the throttle or use the choke, it usually starts with about a one second crank. If it doesn't want to start I will push in the choke a second while cranking without advancing the throttle, that usually does it.

That engine should be set up to run 6000 rpm at WOT to keep it from carboning up. I change spark plugs each spring and use NGK....not Champion.

I run Ring Free or Seafoam every other tank and use a water separating spin on inline fuel filter due to ethanol.

Might be the primer bulb. Once they get old or worn they will leak back down. Also if you tilt the mtr forward after you stop the carbs will lose their prime.

I agree with this, I can definitely see that they are all different already, just want to make sure it really isn't broke before I put it in the "aint broke" category.

Alright great, I just ran some seafoam through the carbs (spray kind) as I had the engine on the hose/muffs the other day, and have been mixing the Mercury Quickleen in the tank as I'm filling up with 92 octane (previous owner said it ran a bit rougher on lower octane, to keep it on premium until I had the carbs cleaned).

Since I just bought it this year, I plan on doing the 100 hour maintenance pretty quickly, and getting the carbs cleaned by a shop while they're at it. I popped one of the plugs out to inspect it after I first bought the boat and it has NGK plugs in there as well, I'll make sure to stick to those.

One thing I haven't done yet is see how far up the throttle is set when it's wide open. I believe I got somewhere around 4k RPM yesterday with it pretty far down. Next time I'm out I'll push it to the limit and see where I'm set at. Based on how far down it was yesterday though when I was hauling #@$ across Ray Hubbard, I would say it needs some adjustment.

You say prevent it from carboning up, I'm assuming running it that hard will burn off any gunk that accumulates in the engine over time, and I should air out the engine a couple of times per trip as part of "maintenance"?

On never using the throttle on warm starts - I'm going to pay more attention when I'm out there to this. Like I said most of the times after I cut it off, if I reach to crank it immediately (or within 30 seconds of turning it off), one bump of the key and the engine cranks right back up.

When I let it sit for 30-45 minutes though, thats when the first crank doesn't start her up again and I go into semi-panic mode out on the water, not wanting to troll / paddle back to the ramp

I'll play it cool next time and try and get a pattern for what works, starting with just cranking it without using the throttle so I can replicate what you are doing, I'll add a bit of choke if necessary, if that doesn't work and I have to fall back on using the throttle, I'll make sure to get note of that.

Having the cold start procedure work 99.99% of the time, I just want to see a warm start (or semi-warm start) procedure that works equally as often.

This may be. I'll re-prime the bulb before the 30 minute "semi-warm" startups and see if that helps me out and gets me closer to a startup like Bronco's.

If that helps out, primer bulb would literally be the easiest thing to replace.

both Gary and Muzzlebrake are right on... there's a ton of XR6's out there that are tha same way... especially tha "have ta pump tha bulb after it sets awhile" part.... might jus be TODAYS GAS....

jan.. 'lectric fuel pump eliminates all that.... jmo

Good to know. And I hear you on the gas part, I was told to never go long without putting fuel stabilizer in the tank after filling up these days.

I'm definitely going to check the primer bulb on the 30m starts now and see what it feels like, I'll bet that is the issue. Plan on running it on the hose today or tomorrow perhaps when I clean it up and get it ready for the lake next week so I will do some tinkering and testing with the semi-warm starts and hopefully have some good info when I get back

like Gary said, some of 'em are jus plain 'ole temperamental and nothin' ya do will change it.. long as it starts and runs a hole in tha wind ya good ta go!!

its jus a basic 'ole carb motor.... gonna have its quirks!

My V175 is similar and in 30 years it has mostly been this way. The harder and longer I run the less it wants to crank right up after sitting. If I am running hard then I am running at full trim and rarely do I think to trim down. If it does not crank right up I just open the throttle in neutral and make sure it is running smooth before backing off. I run Champion 78s in mine. I also have milled heads, use 93 octane, and the hotter plug seems to run better. Boat mechanics brother said to run some L77JC4s. No good. Then I tried some NGKs and ended up back with the Champ perma gaps.

Alright, interesting, looks like a little bit of perspective with regard to plugs. I don't mind trying Champion for a season, I suppose every outboard is a little different so a different plug might help out. Hotter sounds better imo when it comes to plugs. I'm still new to the outboard game so I'm not familiar yet with the specific plug models, I'll do some research into the Champion 78's vs the NGK and make a plan around it.

Good to hear your engine does the same thing! Starting to sound like I have just a typical outboard like TLW says

BUHW'S...... O'Riley's.

NGK recommends BU8H on that motor, my motor is a bit older but runs better with it. Seems like it is hotter than the Champion 76v, tried 77's but the NGK's worked better for me and NGK's work better in my 2 stroke Polaris 4 wheelers also.

As stated before each motor likes different things and you just have to tweak it to find what makes it happy....

stump jumper is tha only guy i've heard of that can make a champion run ina plain 'ole merc! V6.. tha HW is same as 8H only thungsten electrode.. kinda "sounds important" so anything that might make my junk run better as they say!