96' Merc 454 hard starting
 

All,
I have a 96 Crownline with a merc 454 that (at least this year) has been very hard to start. I have had the carb rebuilt by an excellent mechanic, I have verified that when I pump the gas the pumps are spraying gas into the carb, and I have played with about everything else I can think of. Here is what is happening:

First start of the day:
6-8 pumps and hold throttle open just a touch. Cranks for 10-15 secs and it's a 50/50 chance it will light. Sometime I have to play with the throttle a little. Other times I have to stop and pump again.
Every other start after that no matter if it is only 10 min or 3 hours since I shut it off it is harder to start. I have to keep it cranking while it is kind of running for 3-4 sec and play with the throttle. It almost sees to me that the starter is not turning it over fast enough. I am going to change my cap and rotor this week and they are a little worn and dirty but for a 454 this thing just seems very hard to start. Does anyone have any suggestions??

Still sounds like carb problems to me. If its a stock engine why are you pumping the gas 6-8 times. It should have a choke which should take no more than one pump.

The Weber carbs suck. It probably has an internal leak and is leakingh the fuel out of the bowl.

Purple Hornet - The choke is disconected right now as that was recommended to me by a few people sue to the fact that the engine is really never cold (70 degree's +-) and should not need the choke. It is a little easier to start with it off than when it was hooked up.

Since I have read and heard quite a bit about the webers being a bad carb whats a god replacement for them?

The Weber carb and the Edelbrock carbs are similar IIRC, so going from one to the other is not going to get you much. I know on the Edelbrocks tuning the choke can be a pain so it is frequently disabled.

For your hard starting- your comment about the engine turning over slowly grabbed my attention. I had the same problem for many years, until one day my engine just locked up in trying to start it. It turns out that my old-style direct drive starter was slowing crapping out, until that day the nose drive broke off and wedged against the flywheel. The symptoms were similar to hydrolic lock and it took me a long time to narrow it to the starter (more from sheer disbelief than anything else). I replaced it with a newer reduction-gear starter and it now turns over sweet and fast. The newer starter (PG260 ?) is a direct bolt-on replacement and can be had for $150 or less. Your engine, being a 96, may already have the newer style reduction gear starter. So, check the starter !! Also check for proper gounds at the engine block.

In my case, I had two group 27 batteries in excellent shape so there was no chance it was a weak battery issue. The starter originally came off a 1987 Gen IV 454 and I reused it on a 2000 Gen VI 454 (perfectly acceptable- they interchange). The newer starter does save quite a few pounds, perhaps as much as 10 pounds of weight.

When you go to restart it sounds like you are flooding it. Next time out after shutdown just crank the engine over without any throttle pumping. It should start right up. For replacement, I would look for a holley 750cfm vacuum secondary or double pumper.

Dogturd21 - Thanks for the input on the starter. I am thinking that I have an issue in that area as well and it is making my hard starting harder to completly resolve. Whats the easiest way to tell the difference in the starters? I am assuming the newer one will have a gear box of sorts on it.

Blue thunder - I have tired it that way as well but I get the same outcome of the starter basicly trying to run the engine for a few seconds. It's just like it doesn't want to light and it dogs.

The Weber carbs are crappy. I would replace it with eitehr a new edlebrock or Holley 750. Make sure to use a marine carb.

I would lookup your engine on a site that has pictures of parts- my favorite is BAM Marine. You would have to see pics of the old style and new style starters to see the difference. If you can take a pic of your current starter (camera phone, iPhone etc.) and post it or email it to me I can easily tell. Let me know exactly which 454 engine you have and I should be able to look it up.

One way to tell if you have the old style starter is to look for a large Phillips head screw in the center of the main body of the starter (not looking at the end, but in the middle body). By way of pics, look up Ebay item 250221992988 and see the gold phillips head screw in the middle of the body. Although the pic is for a 70's era starter, they were used much later, into the 90's I believe.

Looking at the BAM marine site, it appears that the new style PG260 starter has a 2 7/8 inch end cap, while the older starter has a 3 1/4 inch end cap. Its not that obvious to tell them apart unless you have them side by side- the new style is a bit smaller and lighter

http://www.mercruiserparts.com/selec..._nbr=821723+92

How about doing a compression test. If the compression is low it will be a hard start, no matter what carb you have on it.

Ok, then next time no pumping but put the throttle to wide open and crank it over. Be ready to pull back the stick quick when it fires. Then buy a decent holley carb.

Yep. Could be something other than a carb problem. Your cap and rotor could be the problem. How old are the plugs and wires? When was the last time timing was checked? How about the fuel water seperator? I'd get the obvious/cheap stuff out of the way 1st.

I never had a problem setting a choke up on any carb. The lack of experience is the only problem I see when people say they are a pain and disconnect them.

I agree with Purple. Re-connect the damn choke. It's there for a reason. There's nothing inherently wrong with the Weber carb (Carter AFB) or the chokes they came with. They work very well and are very easy to tune, especially compared to a Holley.

On the 454 give it a pump or two and pull the throttle back to closed until the choke plate also closes (once you fix it) and the motor will start. Do not hold the throttle open.

My experience is with the Edelbrock marine 750, and it was a pain to get the choke correct. Looking at the parts diagrams (this is from memory back a few years) it appears that the Webers and Edelbrock are mechanically similar. IIRC the carb line was sold to Weber way back when and thats why Webers started showing up in the carbed Merc engines.

In fact I really dislike the Edelbrock carb as it has been a real challenge to tune. Actually swapping jets and needles is easy, even on the water, but getting it performing correctly has been nearly impossible. I decided to just rebuild my original Quadrajet 795 and put that back on, and the engine is night and day differenct- better power and better fuel economy. Following the formulas indicates I need 730 cfm so I felt the Edelbrock would be sufficient. Obviously the Rocheter is far more complicated and harder to tune, but it seems to work better over the entire rpm range. That said, I prefer EFI overall.

If the engine is flooded from the bowls leaking, you will only make things worse by pumpng the throttle.

Of course it would. I simply assumed a hard start problem was most likely only to be the defeated choke. Lots of things could be wrong and there could be multiple problems.

I don't understand the problems people have with this carb. It's such a simple unit. Getting the main and secondary jets and metering rods exactly right have nothing to do with hard starts and the choke is so f'in simple.

Check that the float levels are correct and the needles are working.

One thing I found helpful was you can purchase spring-loaded needle and seat assemblies from Eldebrock. Designed for off-road apps in the 750 street carb they can cut down on minor flooding issues on performance boats as well. They are cheap and easy to install on the marine Weber.

So this kit is basically turning the Weber into the Edelbrock ? I agree that actually doing the needles / jets / springs on the Edelbrock is easy, and the full tuning kit gives you all the popular options. But mine never ran well - I guess you get what you pay for, as the Edelbrock and Webers are about the least expensive carbs you can get. The Edelbrock was running about 1/2 the price of a similar Quadrajet for a while.

They are basicly identical except for the exact setup (jets, metering rods and step-up springs).

Do you have the choke wire tied open? If not it may be cooling and going closed when it should be pulled off by vacuum. Next time it won't start hot take of the breather and look at the choke plate to make sure it is wide open. If it is not you found the problem.

Ditto- just disconnecting the wire is not enough, as the choke will tend to close on you and the engine will run poorly or not at all. Either connect the wire, or disconnect AND fasten the linkage back to full off. I did this once and I think the symptoms are that it runs ok at idle and up to about 1500-2000 rpm, and at high rpm it then stumbles / stalls as the choke plate closes up (this is from memory back to 2000 / 2001).

The Edelbrock carb is the easiest carb in the world to adjust the choke on. But like any other carb the engine needs to be stone cold to do it and this may take awhile. For performance I do not recommend it but for a quick starting engine and smooth operation they are awesome for the money. One thing I will also say, if you buy a new one and it acts funny or has a bad stumble its the carb casting take it off and get another one no tuning in the world will fix it.

I am a Holley guy but if I want to sell something and want it to start fast and idle quick a Edelbrock hands down will be stuck on the engine. But then again none of my Holley's have a choke.