PDA

View Full Version : 85 S&S hesitate on holeshot


xtnkshun
08-02-2012, 11:50 PM
Good evening TT'ers,

Took my brand new used 85 out to the lake last weekend for the first time and she performed quite well. She's not nearly as big a restoration as some of the amazing boats I've seen here, but she needs a little love.

Motors cranks easy...cold or hot. Idles good. Runs good at speed and maintained around 170 degree temp all day. Only issue I had was a bog / hesitation on the holeshot early in the day. If I eased into the throttle she was fine. And the bogging problem got less and less as the day went on. The second day it was the same way. Bog in the morning and hardly any after running a while.

I'm certainly not an engine guy, but I felt like she was getting too much fuel at the holeshot.

Any thoughts gurus?

P.s. I burned through about 2/3 of a tank of fuel in 2 days...maybe 2-3 total hours of running. Normal?

madcityskier
08-03-2012, 01:02 AM
Depends how hard you're running her. For general use I see roughly 4-5 gph. Might want to make sure the carb is clean for a starting point.
Oh, and welcome to the MC

madcityskier
08-03-2012, 01:04 AM
By the way, congrats on the boat. We'd love to see pictures.

thatsmrmastercraft
08-03-2012, 10:46 AM
Need to go through the basics first. Spark plugs, distributor cap & rotor, plug wires, fuel filter, check timing, and new points & condenser (if not already converted to electronic ignition). Next I would check to see that the choke is adjusted properly and opening completely within a minute or so. Then I would check for a carb base gasket leak. Could be carb related, but I suspect if you work through these things you will correct the situation. Good luck. Post some pics of the boat please.

Butthead
08-03-2012, 03:29 PM
Check fuel filter .

xtnkshun
08-13-2012, 03:32 PM
Sorry for the delay guys. I've been battling another issue with her.

http://www.mastercraft.com/teamtalk/showthread.php?t=50139

Here is a quick pic I snapped. She still needs some work, but I'm making progress. She got new plugs, new wires, already had electronic ignition, new blue top battery, new bilge, new flame arrestor. PO had straight wired the entire dash (bypassing fuses)...that has also been fixed. Still having the hesitation on hole shot, but it does appear to have gotten slightly better.

Timing is next..although I have never done that. I realized this weekend that the holley carb might actually be an automotive carb rather than the marine version. It doesn't have the yellow finish of the marine carbs, but I need to check the PN to be sure.

I also noticed that the vent nipple on top of the fuel pump that connects to the flame arrestor via a tube is missing also. I put my finger over the hole on the fuel pump where the nipple was while she was running, but that didnt really seem to do anything.

http://www.jabgraphix.com/images/photo_boat_med.jpg

johnlanguab
08-13-2012, 03:36 PM
If the carb has U shaped overflows on the top, it's likely a marine carb.

thatsmrmastercraft
08-13-2012, 03:46 PM
Marine 4160 looks like this.

thatsmrmastercraft
08-13-2012, 03:46 PM
Dead give-away to an automotive carb is un-blocked float adjustment screws.

xtnkshun
08-13-2012, 06:30 PM
Excellent info! Looks like mine is in fact marine. The float adjustments are blocked. The front one has some kind of hard epoxy covering the top. None on the back.

thatsmrmastercraft
08-13-2012, 06:33 PM
Post a pic of the carb and we can tell you for sure.

xtnkshun
08-13-2012, 09:33 PM
Where is the fuel filter located? That's next on my list. I thought I read that there is also a screen in the fuel pickup from the tank also...was I dreaming?

1redTA
08-13-2012, 10:02 PM
You could have a busted spring in the secondary diaphragm, I had one coil busted off and it would stall unless I gave It throttle very slowly

xtnkshun
08-13-2012, 10:38 PM
You could have a busted spring in the secondary diaphragm, I had one coil busted off and it would stall unless I gave It throttle very slowly

Does this require a full carb rebuild or can I just replace the springs? Rookie mechanic.

waterlogged882
08-13-2012, 10:51 PM
..........

waterlogged882
08-13-2012, 10:56 PM
..........

xtnkshun
08-13-2012, 11:06 PM
Thanks Cloaked. Plan on getting back there this weekend. Noticed some small cracks in the pickup hose last weekend. skidim order time! Was a Holley carb standard on the 85's? I guess my could be 25+ years old but if it is it looks DARN good.

waterlogged882
08-13-2012, 11:10 PM
..........

xtnkshun
08-13-2012, 11:16 PM
And I think my fuel cell was replaced at some point. It just doesnt quite fit right. The clamps in the floor hold her down, but a little off. And your 8" filler hose is more like 4" on mine and 2" diameter and doesn't line up with the filler hole in the boat. PITA is an understatement!! Still working on alternative.

waterlogged882
08-13-2012, 11:19 PM
..........

thatsmrmastercraft
08-14-2012, 01:24 AM
You could have a busted spring in the secondary diaphragm, I had one coil busted off and it would stall unless I gave It throttle very slowly

Haven't encountered that yet, but have heard of it happening. I imagine that was a head-scratcher for a while.

xtnkshun
08-14-2012, 09:14 AM
The brackets on these cells will rarely look like they were installed with quality and pride.

Great way to put it. This is one of those nagging problems that I need to fix. The hose is so short and out of whack with the filler hole in the hull that it is putting A LOT of pressure on the gas cap. I don't want it to bust through to the hull.

xtnkshun
08-14-2012, 09:15 AM
Headscratching...I seem to be doing a lot of that lately.

TRBenj
08-14-2012, 09:40 AM
Dead give-away to an automotive carb is un-blocked float adjustment screws.
For the intents and purposes of this conversation, that is not a bad thing to check- most marine 600cfm 4160's have the float adjustment screws blocked. But, as a general rule, that is an entirely incorrect statement.

Holley marine 750cfm 4160:

http://performancecarb.files.wordpress.com/2011/12/750-4150.jpg

thatsmrmastercraft
08-14-2012, 10:44 AM
For the intents and purposes of this conversation, that is not a bad thing to check- most marine 600cfm 4160's have the float adjustment screws blocked. But, as a general rule, that is an entirely incorrect statement.

Holley marine 750cfm 4160:

http://performancecarb.files.wordpress.com/2011/12/750-4150.jpg

It's like talking with my brother's kid's........can't say anything that isn't 100% factual without being corrected:rolleyes::D:D

I was going the keep it simple route.

xtnkshun
08-14-2012, 11:43 AM
Funny...after I bought the boat, I said...'Cant be that hard to work on, basically a motor and a hull'. Boy was I wrong!!

TxsRiverRat
08-14-2012, 12:01 PM
+1 on 4160.

PCM tells the dealers to replace the old fishbowl carbs - not to rebuild them.

xtnkshun
08-14-2012, 12:11 PM
Here is a pic of mine.
http://www.jabgraphix.com/images/photo_carb.jpg

thatsmrmastercraft
08-14-2012, 01:06 PM
Here is a pic of mine.
http://www.jabgraphix.com/images/photo_carb.jpg

Have you got a picture with the flame arrestor off?

xtnkshun
08-15-2012, 08:38 AM
Have you got a picture with the flame arrestor off?

Unfortunately not, I will snap one Friday when I go get the boat. Ordered new fuel line and fuel filter from skidim yesterday. So, I'll either fix the bog or further narrow it down to the carb.

On a side note. I want to say that Skidim is AMAZING. Yes, some of their parts are more expensive than on other sites, but there support is top-notch. I ordered some items yesterday, and someone called me to say that I had chosen the wrong filter and they wanted to be sure I didn't make a mistake. Fixed my order, credited back the difference, and should still be here on Thursday. To me, that is worth a few extra bucks here and there.

thatsmrmastercraft
08-15-2012, 10:14 AM
Unfortunately not, I will snap one Friday when I go get the boat. Ordered new fuel line and fuel filter from skidim yesterday. So, I'll either fix the bog or further narrow it down to the carb.

On a side note. I want to say that Skidim is AMAZING. Yes, some of their parts are more expensive than on other sites, but there support is top-notch. I ordered some items yesterday, and someone called me to say that I had chosen the wrong filter and they wanted to be sure I didn't make a mistake. Fixed my order, credited back the difference, and should still be here on Thursday. To me, that is worth a few extra bucks here and there.

Customer service is their middle name.

xtnkshun
08-17-2012, 11:19 PM
Here is a pic without the arrestor. Is this screen inside the pickup attached to the fuel cell. Mine is a 90 degree elbow with a barb on one end that Hooks fuel line? Also, does the fuel filter just screw off like an oil filter...mine looks just like an oil filter.

--- stupid photobucket...will try again later!

waterlogged882
08-17-2012, 11:27 PM
..........

xtnkshun
08-17-2012, 11:48 PM
Crap. Never noticed that...doesn't seem to work to upload files on iPhone.

xtnkshun
08-18-2012, 10:08 AM
Let's try this again.

xtnkshun
08-18-2012, 10:09 AM
<< SLAP >>

:D

Scroll down under the text box (where you post) and look at a feature called "Management Attachments" CLICK THERE... :D Done deal.

.
I deserve the slap. YOU ROCK Cloaked!

waterlogged882
08-18-2012, 06:26 PM
..........

xtnkshun
08-19-2012, 12:08 AM
Thanks Cloaked. I am going to try and get the screen out tomorrow. And sending unit is shortly behind. Fuel gauge bounces all over the place. Question...the vent tube on my fuel pump, that is supposed to run up to arrestor is gone...could this effect performance?

waterlogged882
08-19-2012, 08:02 AM
..........

03geetee
08-19-2012, 09:11 AM
Good advice Cloaked on doing lots when you are in there for one thing. When you do that it can eliminate a future diagnosis because you know you fixed a certain amount of things that could have gone wrong.

I will have to order a spare fuel pump after reading your post I have been meaning to do that. I also recommend a spare coil, plugs, and rotor because as he said they can fail at the worst time yet are so easy to replace....if you have em.

JTR