454, Bravo 1 Sticking in Forward
10-11-2010, 12:30 PM
#1
Registered
Thread Starter
Join Date: Sep 2010
Location: Maine
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
454, Bravo 1 Sticking in Forward
I recently put this professionally rebuilt 454 in the boat, (Bravo 1). Replaced lower carrier, rear bearing, seals. We take it out to the river to do some final tesing, life is good. Couple of trips later, the stepkid says it's spraying sea water in the engine compartment. Water is leaking out of the weep hole, so I replace the circulating pump. While I'm at it, I take out the distributor to replace the gasket, because oil is pooling on the intake, and I'm thinkin' maybe that gasket is bad. Almost dropped the distributor putting it back in, and when I grabbed it back, rolled the shaft, lost timing. Reset the timing, went to the river to test it, and the durn thang started sticking in forward near idle. Would not go into neutral. I took the lower cable off, put it in neutral, he put the stick in neutral, I reinstalled it. It would work a couple of times, then stick again. It seems to me that it has to be a problem with boat end of the linkage, as the outdrive shifts very smoothly by the lower cable only. I add all this peripheral stuff in here, because I apparently don't know what info is relevant, having got blowback for leaving stuff out. Any ideas?
__________________
1988 Merc 454, Bravo 1, based in Maine, Edlebrock AirGap RPM, Eddie 1410 Carb, Isky MegaHydraulic cam, TB IV, Raw water.
__________________
1988 Merc 454, Bravo 1, based in Maine, Edlebrock AirGap RPM, Eddie 1410 Carb, Isky MegaHydraulic cam, TB IV, Raw water.
10-11-2010, 04:37 PM
#2
Registered
If you disconnect the lower cable, then shift the upper end of things a few times does it jam? If it's shifting fine with the lower cable only, then I would continue upstream from there. Could be as simple as a binding linkage or loose cable.
10-11-2010, 07:54 PM
#3
Registered
Thread Starter
Join Date: Sep 2010
Location: Maine
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
That's pretty much my thinkin', RT - I just worry that that Merc shift linkage mounted to the elbow may be one of those 'gotta hold your mouth just right' deals. They talk about a shift linkage adjustment tool I don't have, and don't think I need. Hope I'm not wrong.
10-12-2010, 07:46 PM
#5
Registered
Thread Starter
Join Date: Sep 2010
Location: Maine
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
Used to be 800 R's in neutral, never saw the tach when dropped in gear. Now it doesn't like to idle below 900 R's. I would have thought that between the timing and carb, the only thing messed with was the timing, and getting that right would bring back the idle. I just don't know where the builder put the timing. I have it at 12 initial right now, figuring the TB IV will advance me 22 more, for a total of 34. I hate flying blind.
10-13-2010, 11:14 AM
#6
Registered
Join Date: Nov 2001
Location: Pennsylvania
Posts: 3,385
Likes: 0
Received 0 Likes
on
0 Posts
Idling high in gear will make it hard to pull out of gear. I have blower surge and wait for the idle to drop to around 500rpm and it clicks in and out easy. There are other possible reasons for a drive to come out of gear hard, but get that "in gear" idle down first and work from there.
10-13-2010, 06:50 PM
#7
Registered
Thread Starter
Join Date: Sep 2010
Location: Maine
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
The idle is turning into a new durn project. I cannot get it below 900 R's, and even then it's got no guts. This thing only has 8" of vacuum. The TB IV module says V824. I gave it about 14 degrees initial figuring a total of 38. I pulled 14 out of my ear. This cam is an Isky with an advertised duration of 270 and 280 on int and exh respectively, and lifts of .542 and .565 in & ex. Lobe centers are 114 degrees apart. Isky says it's RPM range is 2200 to 6500. Would cam specs like that give me vacuum at 8"?
10-14-2010, 11:32 AM
#9
Registered
Join Date: Nov 2001
Location: Pennsylvania
Posts: 3,385
Likes: 0
Received 0 Likes
on
0 Posts
If it is a holley carb, your secondarys may be held open too far. That will make it so you can't turn the idle down.
Are you using a timing light to set the timing? You should set it at 8* base timing as a start.
Are you using a timing light to set the timing? You should set it at 8* base timing as a start.
10-14-2010, 05:50 PM
#10
Registered
Thread Starter
Join Date: Sep 2010
Location: Maine
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
I am using a light - had to hang a mirror and paint the marks with white out. It's an Eddie 1410 carb on an AirGap RPM manifold, with the two idle mixture screws out on the front of it. The manual says they alone feed the idle fuel, so I screwed'em in till they seated, and the engine R's only started dropping at 1/2 turn out. They were originally about 3 1/2 turns out. I can put them anywhere from 1/2 to 3 1/2, and see no change in the idle. Down near the 1/2 turn end of this range, the transition from idle up gets crappy, so I have them at about 2 turns at the moment. I figure the jitter in the vacuum gauge needle is from all the cam overlap. I got the ugly feelin' that the only reason I have an idle is because I have the idle speed screw cranked in far enough to crack the primaries. Oh where, oh where is my vac leak?
