318 sputters under load

This forum is for comments and the exchange of information relating to Trojan Boats and boating. Please do not post used parts or boats For Sale in this area. For general, non-boating topics please use our "General Discussions" section.

Note: Negative or inflammatory postings will not be tolerated.

Moderators: BeaconMarineBob, Moderator, BeaconMarineDon

Post Reply
drbbqking
Sporadic User
Posts: 92
Joined: Tue Aug 02, 2011 12:33 pm
Location: wilson point maryland

318 sputters under load

Post by drbbqking »

I have 2 chrysler 318's the port has started to sputter under a load. popping and hesitation at 6 knots it runs well but as I add throtle it starts to pop and sputter stall and backfire at the carb any ideas as to a fix I am using m.s.d. so I am getting a hot spark
1973 f32 twin 318's raw water cooled
User avatar
Commissionpoint
Active User
Posts: 1197
Joined: Wed Oct 05, 2011 11:59 pm
Location: Diamond Point on Lake George, NY

Re: 318 sputters under load

Post by Commissionpoint »

whats your total advance, and how is the condition of your fuel/water seperators?
1978 F-32 "Eclipse"
Merc 305 SBC's
1.52:1 Borg Warners

1983 Correct Craft
Commander 351 Ford (PCM)
1:1 Borg Warner

There are 350 different varieties of shark, not counting loan or pool.
User avatar
prowlersfish
2024 Gold Support
2024 Gold Support
Posts: 12645
Joined: Sat Nov 05, 2005 6:56 pm
Location: Lower Chesapeake Bay ,Va

Re: 318 sputters under load

Post by prowlersfish »

Look the Cap and check your wires . what type of "m.s.d" unit are you using ? That also could be a proplem . You could also have a fuel issue . check your filters like CP said . but you could have trash in the carb. As you see there is not just one thing that can cause a proplem .
Boating is good for the soul
77/78 TROJAN F36 Conv.
6BTA Cummins diesels
Life is to short for a ugly boat :D
jddens
Moderate User
Posts: 676
Joined: Tue Jul 24, 2007 5:02 pm
Location: Northern CA

Re: 318 sputters under load

Post by jddens »

I agree, the MSD unit could be your problem. I had an MSD unit on my hot rod and it failed, the symptoms were like yours only intermittent......
1972 Trojan Sea Raider F30 - FI 350's "Time Warp"
1998 Kawasaki ZXi 1100
1972 Chevy Fleetside Shortbed hotrod.......450hp
10.5 Newport Inflatable w/15hp Rude
User avatar
Paul
Active User
Posts: 1141
Joined: Fri Jun 10, 2005 1:02 pm
Location: Windsor Ont.

Re: 318 sputters under load

Post by Paul »

I've had that problem due to a partially blocked anti siphon valve at the top of the fuel tank.
Paul
"Cruise Control" 1978 F-26HT
"No Control" 2012 9' Grand RIB
drbbqking
Sporadic User
Posts: 92
Joined: Tue Aug 02, 2011 12:33 pm
Location: wilson point maryland

Re: 318 sputters under load

Post by drbbqking »

what are the initial setting for the carb ??? I have 3 screws 2 are the idle but what is the big one between them and what is the setting????
1973 f32 twin 318's raw water cooled
larryeddington
2024 Gold Support
2024 Gold Support
Posts: 1870
Joined: Mon Sep 28, 2009 5:08 pm
Location: Canton, TX Boat on TEXOMA

Re: 318 sputters under load

Post by larryeddington »

I assume you have Cart AFBs on both engines. Mine only have two screws which are the idle adjustment screws, high speed jets are fixed. If one engine is fine I would start swapping some parts from one to the other. when it cures you will have the culprit assuming the other engine is running well.
Larry Eddington
1984 F-36 Tri Cabin "The Phoenix II"
1978 F-28 "The Phoenix"
Fish Master 2350 Bay Boat
9.5' Dink
User avatar
ready123
Ultimate User
Posts: 1841
Joined: Sat Nov 08, 2008 5:53 pm
Location: Mactier, Ontario Canada
Contact:

Re: 318 sputters under load

Post by ready123 »

Can you switch the fuel supply? If you have a fuel manifold put the bad engine on the good engines tank and see if the problem goes away. That will answer the fuel supply concern..... Then you are down to carb and ignition problems and can work through those.
I had a partially blocked siphon valve at top of tank that prevented enough fuel flow at anything above low speed travel which showed same symptoms.... Mechanic had run to distributor problems first and it was not there.
Michael
Rum is the reason Pirate's have never ruled the world
Done Dreamin'
1987 President 43' Twin Lehman 225SP Turbo
Highfield 310 Ally 15 HP Yamaha 2cycle
1978 F32 Sedan twin 318 Chry SOLD
Safe Cove Marina, Port Charlotte, FL
User avatar
P-Dogg
Active User
Posts: 959
Joined: Wed Jun 22, 2011 7:15 pm
Location: Near Baltimorgue, Murderland, where they prove every day that gun control doesn't work.

Re: 318 sputters under load

Post by P-Dogg »

Two transposed spark plug wires would cause this problem. You didn't say, but let me guess: It spools-up fine in neutral, but not in gear?

Here's the deal: At low power output, the other cylinders are able to compensate for the loss of power from the "missing" cylinders. When you accelerate under load, the vacuum advance causes the spark timing to now occur when the intake valve on one of the screwed-up cylinders is still open, causing the backfire through the carb. As alluded to earlier, check to make sure that the plug wires are firmly on the plugs, and that they are in the correct order at both ends. And be sure to let us know what the solution was.
I needed a less expensive hobby, so I bought a boat!
todd brinkerhoff
Moderate User
Posts: 696
Joined: Sun Aug 15, 2010 11:56 am
Location: Finger Lakes, NY

Re: 318 sputters under load

Post by todd brinkerhoff »

When was the last time you changed the plugs. If its been awhile, pull one out to see what it looks like.
1991 Trojan International 10.8 Meter Express hull# 003 - 454 Crusaders
1961 Century Raven 22 - Gray Marine 327

Image
http://s1086.photobucket.com/home/Todd_ ... hoff/index
User avatar
Martino
Registered user
Posts: 67
Joined: Sat Dec 02, 2017 8:07 am
Location: Detroit Michigan

Re: 318 sputters under load

Post by Martino »

Any updated info or results to the problem? Has it been resolved? Im also experiencing the same issue with my 1980 F32 with new 360's. Carbs are rebuilt. Anti syphons are good. Checked timing. Went through the suspected port carburator three times and even swapped the starboard carb to the port engine and it ran good.
Post Reply