acceleration lag/hesitation problems

C

cjniemiec

New Member
Jun 10, 2008
16
chicago
Boat Info
sea ray sport 185
Engines
merc 190 hp
I'm desperate for some guidance.

Boat purchased in 2006 - EVERY year I have communicated to dealer a lag/hesitation with the engine when accelerating prior to getting on plane. If I do not pull back on the throttle, the engine will die. Carb was replaced, yet, still have prob.

BATTLED with dealer this weekend to fix once and for all - they are going to do a tune up in hopes that resolves it.

Your thoughts?

At what point do I go the lemon law route - or is that even silly to mention?

The boat has had this problem EVERY summer! And has yet to be fixed!!!!!!!!!!!!!!!

Any and all help is appreciated!
 
Have you tryed diffrent fuel? Try getting fuel from a diffrent place with a higher octane rating. Timming could be off as well as carb issues. Dont think a new carb will fix the issue. Have yours tuned properly for your engine. New carbs are set to a broud range of engines and will need to be tuned to your engine.
 
I agree with 'Oldsman' - You need to have the motor brought up to spec - Timing, carb adjustment (if required), potential throttle adjustment etc. .. .after that if the hesitation persists its on the dealer to make good.

Is the dealer running it post fix and telling you its fixed prior to returning it to you ? I would insist they put it in the water with you there next time they tell you its fixed and demonstrate this.

Lemon law is a long drawn out process that I don't recommend (I went through it with Chrysler) and suggest you try everything to avoid it. I understand that this is frustrating. . . . .

Also are you only working with the service manager at the dealership ? elevate your issue with everyone in the dealership, remember the squeaky wheel . . . .

Reags
 
What is the condition of your spark plug wires??
 
#1) As you can see from the replies, your issue can be caused by many things.

#2)I am not familiar with a lemon law for boats. If you are out of warranty and your current mechanic can not fix the boat to your satisfaction then go to a different mechanic and know it will cost you out of pocket.

Things I would try, in order:
#1) new fuel filter. Invert old filter over glass jar. Let it sit over night. Look at fuel and see if you have any signs of water or phase separation.

If no fuel issue and your lag issue remains:

#2) New spark plugs.

If your lag issue remains:

#3) Balance of tune-up items (plug wires, cap, rotor)
 
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You guys are great for taking the time to pass along your thoughts....let me add a bit to the story....
1. The boat was purchased and used in Wisconsin
2. The lag/hesitation upon accelerating towards getting on plane has been an issue communicated to the dealer EVERY year - each year they have worked to resolve it - the most recent being a carb replacement
3. This past fall they said they would tune up the boat - this spring the service manager said he wouldn't?!?!?!?! I had it in writting, held my ground, and eventually had the manager of the shop agree they have a responsibility to get this boat up and running properly once and for all (I was ready to blow up at the service manager - I have 13 pages of emails communicating my frustration with this issue over the years!)
4. It is my understanding they did NOT do a tune up when the carb was replaced - in your opinions, should it have been????
5. THe service manager this spring was pinpointing the problem due to "slow throttle" movement. I communicated I tend to "pamper" the boat when getting on plane (I don't hit it hard) he claimed that is why I have the problem. I contacted Mercruiser - they said their engine should NEVER lag - the service manager said the area rep disagrees with this statment - your thoughts?????
6. Yes, they always run it in the water after it has been worked on - I ALWAYS communicate the minute I experience the ongoing problem when I'm on my own.
7. Naturally there is corrosion issues and the tune up should resolve that concern - but it is a stretch for me to think this is the solution to my problems seeing that the preoblem existed the first year I owned the boat (I expect some form of corrosion issues after 4 years).
8. I suggested a new fuel filter - but why am I brainstorming this and not the service manager????

Again, I appreciate your guidance on this - any and all thoughts are GREATLY appreciated!
 
My best guess would be the problem is fuel air mixture related. Specifically too much air, not enough fuel. Since you have replace the carb already and I assume the dealer is bright enouth to verify proper accellerator pump adjustment, I would look for an air leak in one of the vacuum hoses, fittings or the intake manifold itself.

If you want to try something simple, adjust or wire the choke linkage so that the choke plate stays approx. 2/3 closed and then accellerate hard. If the hesitation is much improved, it is fuel air mixture related.

An intake manifold, hose or hose fitting would make sense since the problem has occured since new and could be a badly cast manifold or machined with warped mating surfaces to the block or where the manifold meets the carb.
 
Scott:

Thanks for the feedback - at this point, I have little hope the service department is bright enough to figure out how to start the boat up.

I will pass along your trouble shooting ideas - an autos guy at school guessed it was related to a fuel issue as well - why these ideas haven't been communicated to me in the past from the service department is confusing.

I'm at a loss of words how I can receive some rational suggestions in less than 24 hours here and get absolute crap for feedback from the dealership.

Anyone have an opinion on the "slow throttle" topic? I am led to believe this is bs - shouldn't I be able to use a slow throttle in picking a young child out of the water on skiis without any lag/hesitation from the engine?
 
i just keep thinking the accelerator pump arm is adjustable, it normally has 2 or 3 adjusting holes, the farther back the more the volume that squirts. jmt
 
Please tell us what the dealer said.

Can they recreate the lag issue?

Do they agree you have a lag issue?

Are you under warranty? Has this work been covered under warranty? If so, would you be covered if you went to a different dealer?
 
At this point, the dealership is acknowledging responsibility in getting the boat up to par - although I'm beyond 2 years of purchasing the boat, I've persisted that this is an issue that has existed from day one and has yet to be properly diagnosed/fixed. If I didn't have a history with the same problem, my expectations of the Dealer covering the work on it would be different.

Have they observed the problem? This is a bit tricky - VERBALLY I was told for the first time...no, this past spring - which was a complete joke.

BECAUSE

I have in writing, verification that they have observed the problem on two diffent occasions/years - this ultimately was part of the reason why they are willing to do work beyond the boats warranty (it has yet to be fixed/resolved despite their previous efforts).

I went on the water this past weekend with them and was unable to recreate the lag - BUT- I'm not convinced they didn't warm up the engine before I arrived (it happens more frequently with a cold engine).

All work has been covered under warranty or them accepting the cost (including the current tune up) because the issue has yet to be resolved - I do not plan on working with another shop.

Any thoughts on the idea it is operator error (using a slow throttle to get on plane?????)

Other ideas/suggestions on what I can/should do?

Again, I appreciate everyone's insight on this!
 
cjniemiec said:
Any thoughts on the idea it is operator error (using a slow throttle to get on plane?????)
Click to expand...

No, I think if you're gradually increasing the throttle you're doing it right. All carb's can exhibit some lag, but typically only if you "throw" the throttle down.

You know, when it comes to machines, my general rule is "all bets are off when it's cold". Meaning, if you're only experiencing a problem when it's cold, don't worry too much.

Does your boat have the Turn Key Start system? That thing can be good or bad. It's one of those things that is either the best invention in the world, or a real PIA.

Going out for a ride with the mechanic was a good idea - do it again, if you have to.
 
cjniemiec said:
.....I went on the water this past weekend with them and was unable to recreate the lag - BUT- I'm not convinced they didn't warm up the engine before I arrived (it happens more frequently with a cold engine).......

Other ideas/suggestions on what I can/should do?

Again, I appreciate everyone's insight on this!
Click to expand...
Never gun a cold engine! The internal parts are broken-in mosty at operating temperature, and the engine needs to be babied until it is fully up to temperature. Lag when the engine is cold is a good thing - it minimizes the abuse, and also proves the mixture is about right when the engine is warmed up.

It is fuel injection that has us all thinking that engines should run fine when cold. Carbureted engines have always needed to be warmed up. You simply cannot tune up for cold running, because by the time you get to the adjustment, the engine is warming up.
 
Just to clarify - I would never gun a cold engine - what I was trying to communicate is that I have concerns the shop had my boat in the water warming up before I arrived - meaning that if it was going to recreate the lag issue while I was in the boat, it was going to be highly unlikely - BECAUSE they they had it fully warmed up.

I always warm up the engine for 5-10 min before I do a slow, consistant pull out of the water - the lag most often occurs during this first initial pull out of the water.

I'm picking up the boat today - the shop says it was tunred up - in your opinions, is this something that most definately should have been done when the carb was replaced?

Hopefully all is well from here on out - but my concern is what my next step is if it is not?!?!?!?!?!?

Thanks for the feedback!
 
Definitely sounds like a weird problem, and like most weird problems, some detective work of your own may be in order. Here are some noodles...in no particular order.

If the basics were right (completely agree on a wire breaking down...ohm meter check time!) and carb had been replaced, and I had a couple of hours...bored, at the dock...

I think I would double check to be sure I was getting timing advance on acceleration. Hook up a timing light...be sure your base timing is accurate, then accelerate and look to see that it advances. Not sure the exact specs...bet they are about 6 to 8 degrees, but I would want to see at least four.

When you accelerate (and are bogging down) do you smell a funny exhaust smell? Lean engines have a different exhaust than rich ones...you may have noticed and may not.

Is the acceleration issue every time? I wasn't sure from the post. If so, I would take a tape measure and goggles and measure the prop carefully and then double check with "prop guys" that it is the right one. Unless you have DTS (Digital Throttle and Shift..."fly by wire") its just a cable to a carb, so you really shouldn't have a delay curve built into the connection...

Edit...sorry, I just caught the last two posts...if it is cold operation related, most of the suggestions I had (other than the wire) are utterly worthless. If I was chasing weird cold gremlins, I would be looking at items that have an effect on temperature inputs...thermostats and temp sending units.
 
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Update....

I picked the boat up from the dealer this past weekend - the dealer did a "minor tune up" which I thought was a little weak on his end - but did cover the $300 cost - I think this just include a new "distributor"? cap and some minor adjustments/checks.

The first time out after warming up the engine I had a MINOR lag, but it held the acceleration - the rest of the day I did not encounter it.

Hopefully this is a sign of my problems being behind me, but time will tell - as one mentioned, if this is happening pretty much only on the INITIAL pull out of the water for the day...I can probably chalk it up to a cold engine (although I warm it up to 170 degrees).

Any thoughts/suggestions are appreciated.
 
Need more input .....

My hesitation/lag issue appears to be a minimal problem now - has happened 2 of last 10 times took the boat out - both times being the first push to get on plane after being on the boat lift for a number of days.

New problem...

The boat 3 times this weekend coughed and spit for about 10 seconds AFTER I shut the engine off (turned the key). I even removed the key twice and it continued.

My neighbor says not to worry - happens once in a while - but 3 times in one weekend?

Why is it doing this?

What should be my expectations from the dealer, related to this problem.

I'm going to check the forum for a topic on this - thanks in advance for your thoughts.
 
Do some searches for "dieseling" or "run on". There's been some very good discussions/threads about this. One in particular has some posts in it by Bon Bini (very informative). Use his name as a qualifier in the search.

For whatever reason, this has been more of an issue for carb'd V-6's than the 4's or 8's. And some V-6's exibit the problem, while others do not. Typically, we'll see this happening more in the Fall when on-the-road gas stations change their formulation (good for cars, bad for boats). Sometimes adding an octane improver will help.

The run-on is primarily caused by too much heat build-up in the engine compartment. Running the blower full time or letting it idle for a few minutes before shut-off usually takes care of the problem.

It could be bad gas.

There are mechanical apparatuses that can be installed to take care of this (completely shuts off the air intake) - but it's best to try and solve the problem before doing that. Sometimes these apparatuses become more of a problem than they're worth (shutting the engine off during docking maneuvers, for example).
 
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