Starting carbureted engine

[Over40footin]

New experience for me starting a carburetor boat,  350 mag mercruiser eldelbrock 4 barrel carb with electric choke.  

Other forums have mentioned the prime technique with the throttle, this works Beautifully for me however the perfect pass stargazer does not stay roundup on the servo motor.

I guess no big deal just annoying. I don’t want to break the perfect pass motor?

My main question is the turn key has a push and turn function to start.  Is this the choke for the start of the engine?  If so how should I use it? Every start: push and turn; or try to start without pushing the key in?

 

[justgary]

2 hours ago, Over40footin said:

New experience for me starting a carburetor boat,  350 mag mercruiser eldelbrock 4 barrel carb with electric choke.  

Other forums have mentioned the prime technique with the throttle, this works Beautifully for me however the perfect pass stargazer does not stay roundup on the servo motor.

I guess no big deal just annoying. I don’t want to break the perfect pass motor?

My main question is the turn key has a push and turn function to start.  Is this the choke for the start of the engine?  If so how should I use it? Every start: push and turn; or try to start without pushing the key in?

 

Priming with the throttle should squirt fuel into the throats.  A few short strokes should do as well as one long one if the PP likes that better.  Remove the spark arrestor from the carb and watch as someone pumps the throttle.  You will soon get a feel for how much the engine wants.

You can also watch the choke while someone pushes the key in to make sure it is actuating properly.  It may have a kickdown lever that engages as you pump the throttle, so watch it to see how it works.  If it has a kickdown stop, you would move the throttle forward, push the choke button, move the throttle back, and it will set the choke on a high idle stop until you use the throttle again.  Yours may be simpler, and only choke while the button is pressed.

Since you are in Florida (which part?), you may only need choke on the first start of the day, and maybe then only if the air is pretty cool.

[Over40footin]

Thanks for responding, I will experiment with the flame arrestor off, like you mentioned hopefully the choke is working like it’s supposed too. I have to be honest I’ve pushed the key in and choked it most every start.  I never new the key had the 2 start options. I’m in Lakeland FL I’ve owned the 1994 echelon since February 2019. It’s been enjoyable owning and working on it, learning as I go.

[Woodski]

@Over40footin - No issues on the priming technique with PP, in cooler weather 2-3 pumps should work great.  Once warmed up, no need to prime.  The electric choke will set itself simply as 12 volts goes to the unit, there is not really a button push to engage unless yours was changed.  The electric choke is adjustable, you simply loosen the three screws around the black housing and twist the housing one direction or the other depending on the needs.  You will need to understand which way to go, either richer or leaner to improve the operation.  If you don't know, leave it alone for now.  Your PP may have wound the string backwards, there are several documents and videos on the PP website to review to correct if that is the case.

[Over40footin]

Thanks, I may need to open the choke more, because It’s been a hard to start engine.  

initially I replaced all things that I read about on this forum: spark plugs, wires, rotor, fuel filter, oil change, new impeller, new 140 degree thermostat.

now I may just need to adjust the choke?

[Over40footin]

Correction: 1994 echelon with a new Holley carb, supposedly put in right before I bought it.

im just getting on the lake now, fingers crossed.

[Woodski]

@Over40footin - What engine does that boat have?  Specific engine marinizer, reason I ask, that era Echelon came mainly with Mercruisers which used a Weber carb (same as an Edelbrock or Carter AFB).  Holley's use a different bolt pattern to the intake manifold and are more common on an Indmar.

[Over40footin]

Mercruiser 350 mag 5.7 Holley carb. 
 

my lake test is going ok. I turned the lean black thing to the right. 2 notches 

starting is much better!

the engine runs perfectly up to 36 mph, when I push it to 40 mph the engine surges without throttle input.  I saw 5800 at one point then back to 3900 speed stayed around 39-42.

is this a setting on the perfect pass? Or is it detonation issue. Engine is running cool.

I may need to start a new thread and do more research. 
 

for barefooting I like to go 40mph for 1 foot practice.

 

 

 

 

 

 

[Over40footin]

I’m thinking it’s either the mechanical fuel pump or something to do with the floats in the carburetor?  Mind you I have zero experience with either of these.  
I know I did a thorough tune up and the boat performs beautifully up to 38 mph. WOT rpm is digital on perfect pass only (the tach is there but the ignition wire was taken off the tach and goes to the perfect pass. Not sure if I Could remedy this? ) Engine seems to kick in turbo mode rpm goes all over between 5800 to 3900 speed stays more consistent 39 to 42. I responded to the rpm shooting to 5800 by bringing throttle back down. I’m not sure if I’m at WOT because the engine is acting crazy and I don’t won’t to push it too hard.

[justgary]

2 hours ago, Over40footin said:

I’m thinking it’s either the mechanical fuel pump or something to do with the floats in the carburetor?  Mind you I have zero experience with either of these.  
I know I did a thorough tune up and the boat performs beautifully up to 38 mph. WOT rpm is digital on perfect pass only (the tach is there but the ignition wire was taken off the tach and goes to the perfect pass. Not sure if I Could remedy this? ) Engine seems to kick in turbo mode rpm goes all over between 5800 to 3900 speed stays more consistent 39 to 42. I responded to the rpm shooting to 5800 by bringing throttle back down. I’m not sure if I’m at WOT because the engine is acting crazy and I don’t won’t to push it too hard.

Could be fuel pump, floats, spark advance sticking (if it is mechanical), crud in the high speed jets, wrong jets, wrong metering....

Since it's a new carb, it may need to have the jets and things changed.  Does it have a wedge under it to level the float bowls?

[Over40footin]

In other words it’s way over my head! Time to find a mercruiser mechanic I can trust.

[Michigan boarder]

11 hours ago, Over40footin said:

In other words it’s way over my head! Time to find a mercruiser mechanic I can trust.

Said every boat owner everywhere!

As @Woodski said the stock carb on that engine is a Weber, specifically a 9772SA.  A bolt on rebuilt is $328 with shipping, and might be faster than trying to find a good shop/mechanic.  You can be into $300 pretty quickly in labor alone.  I just put this one on my engine about a month ago.

 

[Woodski]

@Over40footin - here is another item to check, if your speed is fluctuating +/-  5 mph and your engine is fluctuating +/-  2,000 RPM, I would verify your transmission is not slipping and engaging, first item to check is fluid level.    Engine speed to boat speed ratio should be 100 RPM : 1 mph or very close to that at all speeds using an original supplied prop or similar pitch replacement.  A good step would also be to change fluid, for the Velvet Drive trans, I much prefer hydraulic fluid (as recommended in the manual) over ATF which is a common fluid in many transmissions.  Hydraulic fluid translates to a smoother and quieter operation of the transmission.

[Over40footin]

Thanks, I was told by the dealer I bought the boat from that they installed the Holley carb to replace the wrong one on it?

the transmission fluid is fresh ATF and level checked good.  Shifting seems normal.

 I will attach pics tomorrow, I’m gonna run the boat again.

for this engine is max rpm 5000. 5500, or 6000?  
 
at idle it reads 900 I put the boat in gear and it goes to 750. No problems until rpm gets to 3900 then it goes wacky.  
 

its like the engine spools up and accelerates un commanded.  And it sounds a little like it may backfire especially when I throttle down. 

 

[solorex]

1 hour ago, Woodski said:

@Over40footin - here is another item to check, if your speed is fluctuating +/-  5 mph and your engine is fluctuating +/-  2,000 RPM, I would verify your transmission is not slipping and engaging, first item to check is fluid level.    Engine speed to boat speed ratio should be 100 RPM : 1 mph or very close to that at all speeds using an original supplied prop or similar pitch replacement.  A good step would also be to change fluid, for the Velvet Drive trans, I much prefer hydraulic fluid (as recommended in the manual) over ATF which is a common fluid in many transmissions.  Hydraulic fluid translates to a smoother and quieter operation of the transmission.

What hydraulic fluid do you use?  I've always used ATF, but notice it's a bit harsh/clunk going into reverse.  If hydraulic fluid helps, I'm definitely would be sold on it.

[Woodski]

@solorex - Mobil 423 / 424 hydraulic fluid, any good 10 wt. hydraulic fluid will do fine, a c3 or c4 rating per the Velvet Drive manual.  It smooths out the harshness and idle clatter you are probably hearing.  Restores the box to a true velvet drive:-)

[solorex]

On 8/4/2020 at 9:01 AM, Woodski said:

@solorex - Mobil 423 / 424 hydraulic fluid, any good 10 wt. hydraulic fluid will do fine, a c3 or c4 rating per the Velvet Drive manual.  It smooths out the harshness and idle clatter you are probably hearing.  Restores the box to a true velvet drive:-)

Thanks good to know

[Michigan boarder]

On 8/4/2020 at 11:30 AM, Over40footin said:

Thanks, I was told by the dealer I bought the boat from that they installed the Holley carb to replace the wrong one on it?

the transmission fluid is fresh ATF and level checked good.  Shifting seems normal.

 I will attach pics tomorrow, I’m gonna run the boat again.

for this engine is max rpm 5000. 5500, or 6000?  
 
at idle it reads 900 I put the boat in gear and it goes to 750. No problems until rpm gets to 3900 then it goes wacky.  
 

its like the engine spools up and accelerates un commanded.  And it sounds a little like it may backfire especially when I throttle down. 

 

Idle should be around 650 then 550 in gear.  900/750 is high.  That's a simple adjustment at the throttle cable linkage.

My original engine 94 Echelon with the original prop ran at 46mph at 4,600 RPM.  You mention 5,800 RPM earlier above, that seems WAY too high, which supports @Woodski's theory of the transmission slipping.  There simply should be far more resistance to your engine than to allow it to go that high.  Now that I type this, it reminds me that my tach has been acting funny this season and bouncing around a lot, perhaps your tach is failing?

[Over40footin]

Thanks again for everyone’s thoughts on this. The latest concerns are transmission related and I remembered seeing Ron Tanis YouTube video on the drive dampener in the bell housing absorbing the pulses from the engines fly wheel as the pistons fire. This might be my issue!

I don’t want any damage to the transmission so I‘m going to follow this lead first. And talk to Ron at skiboatpartsonline.

also a little side note I busted my eardrum barefooting yesterday so I’m out of the water for a few weeks so my ear can heal.

[Over40footin]

Talked to Ron he believes I’m low on transmission fluid and fears I’ve done damage to the transmission. Getting the fluid level right is gonna be key to the surge in RPM.

 

[Michigan boarder]

2 hours ago, Over40footin said:

 

also a little side note I busted my eardrum barefooting yesterday so I’m out of the water for a few weeks so my ear can heal.

That's the one injury I've eluded so far, but know plenty of guys that have done it.  Hope it heals up!

[Over40footin]

Instead of tuck and roll, I turned my head sideways to shield my face.  For the future I’m gonna try to face the boat more during my wake crossings.

[Rednucleus]

That motor should have a rev limiter at about 47-4800; I doubt it's actually turning 5800

[Over40footin]

Hope your right, about the rev limiter. it’s a new tach, same send wire hook up?  Normal operation to 3900rpm good hole shot.  Prop has one minor ripple on the end of one blade. (3 blade prop, original perhaps)
at one point it jumped to 6000.  But the speed never went above 40 mph.

Im gonna get as much transmission fluid out and put fresh ATF in this borg Warner velvet drive with a 2 qt capacity. Get the fluid right and I’m hoping to report back with an awesome run. 
 

[Woodski]

I don't recall the Thundervolt IV ignition (which is what mid 90's Mercruisers use) has a rev limiter, the hull does a very good job of that.  

@Over40footin - new tach, make sure the 4-6-8 cylinder selection switch is in the correct position if applicable, if not it will read incorrectly.  That does not explain the surging, but can be an issue.  On the Perfect Pass, it can surge or hunt when engaged if you are running below the set speed and it would act up if it is not getting a good tachometer signal or if the ground connection is marginal.  Perfect Pass is very sensitive to ground connections and a strong throttle return spring.  Given a mechanic changed the carb, if they are not PP savvy they won't know to ensure a strong return spring.  Can you ask the mechanic, if he changed from the original Weber and if yes, why that was done?  The OE Weber carb on these engines is fine and works well.  If he swapped Holley for Holley that is different.

Just a reminder from a previous post and my experience, they originally came with Hydraulic fluid not ATF,  when you use ATF you can expect the box to not be as smooth and quiet compared to hydraulic fluid.  A couple of other people have experienced the same.  Hydraulic fluid also reduces the low speed clatter.  When you drain, don't forget to drain out the transmission cooler.