1995 OMC 5.0L IO starting procedure? Stalls when going into gear

[ggundersen3]

I bought the boat last fall and am using it this summer. It started and ran good several times until today. I have 2 questions here: #1-What is the correct starting procedure when the boat has sat unused for a few weeks? Here's what I thought it was: Put control /throttle in neutral, push throttle all the way down twice to prime it, then bring it back to about 1/8 throttle and turn the key. It started right up every time. I'd let it idle high for a few minutes, then bring it down to idle speed, put it in forward gear and away we'd go.
Today, I did the same procedure and it almost started but didn't, I primed it one more time, put it at about 1/4 throttle and she started right up and ran for 10 seconds and stalled. 3rd try doing the same thing it started and stayed running, until I brought it down to idle speed, I let it run at idle for a few minutes, as soon as I put it in gear, it stalled, I repeated this but it kept happening. I never did get underway on the lake.
Am I doing this wrong? Am I flooding it? Am I not priming it enough? Which is the correct procedure to start when its been sitting? As far as that goes, also which is the correct way to start it when engine was just run and is still hot? But I'm mainly looking for an explanation on starting after long periods( a few weeks or so) of not being run.
Question #2: How difficult is it to replace the neutral safety switch? About 90% of the time it functions correct but 10% of the time there's "nothing" when turning the key until I jiggle the throttle level, then the starter cranks. I appreciate all the help/info very much!

 

[Sparkinator]

I assume you have the OMC/Volvo Penta joint venture drive with the Ford 302 with the Holley carb. That was what manufactured in 95. There are manuals online for the Volvo with the Ford engine and Holley carb. It’s the HU or early NC model Volvo. There is an electric choke on the Holley that is adjustable for better cold cranking. There are YouTube videos as well.
Just let us know what type drive you have. If it’s the silver OMC cobra with the hump on top then it’s more than likely the same as the Volvo. The older OMC drives have the flat top on the drive.

 

[Scott Danforth]

shift cable - check the ESA module

you can adjust the neutral safety switch

 

[ggundersen3]

I assume you have the OMC/Volvo Penta joint venture drive with the Ford 302 with the Holley carb. That was what manufactured in 95. There are manuals online for the Volvo with the Ford engine and Holley carb. It’s the HU or early NC model Volvo. There is an electric choke on the Holley that is adjustable for better cold cranking. There are YouTube videos as well.
Just let us know what type drive you have. If it’s the silver OMC cobra with the hump on top then it’s more than likely the same as the Volvo. The older OMC drives have the flat top on the drive.

Thanks Sparkinator. Mine is an OMC/Volvo. You are correct however the drive was replaced a few years back by the previous owner with a replacement Volvo Penta Cobra SX

 

[Sparkinator]

The stock carburetor on the Ford 302 (5.0) is a Holley 2300 2v (2 barrel) with electric choke. There are videos on how to set the idle and the choke for better cold cranking. Just make sure that’s what you have.

 

[Lou C]

While it has an electric choke, a marine inboard carb does not have a fast idle cam like it would in an automotive appliction, so after starting and putting it in gear there is no fast idle. This means that for it to not stall it has to be in near perfect tune and carb adjustment. Make sure the choke closes all the way or nearly so and that it gets pulled open slightly as soon as the engine starts. With the electric choke it will usually open pretty fast, like within 3 min or so. You can adjust it to open a bit slower if need be. What you experience is actually pretty common on the older carbed inboards due to the lack of fast idle, which on a marine engine would be dangerous vs an auto appliction where you have brakes to slow you down. So it may be time for a general tune up and carb adjustment. I do alway warm up the engine before casting lines off. These carbed engines are not like EFI engines, they need a bit of warm up before a load is put on them so they don't stall.

 

[ggundersen3]

While it has an electric choke, a marine inboard carb does not have a fast idle cam like it would in an automotive appliction, so after starting and putting it in gear there is no fast idle. This means that for it to not stall it has to be in near perfect tune and carb adjustment. Make sure the choke closes all the way or nearly so and that it gets pulled open slightly as soon as the engine starts. With the electric choke it will usually open pretty fast, like within 3 min or so. You can adjust it to open a bit slower if need be. What you experience is actually pretty common on the older carbed inboards due to the lack of fast idle, which on a marine engine would be dangerous vs an auto appliction where you have brakes to slow you down. So it may be time for a general tune up and carb adjustment. I do alway warm up the engine before casting lines off. These carbed engines are not like EFI engines, they need a bit of warm up before a load is put on them so they don't stall.

While it has an electric choke, a marine inboard carb does not have a fast idle cam like it would in an automotive appliction, so after starting and putting it in gear there is no fast idle. This means that for it to not stall it has to be in near perfect tune and carb adjustment. Make sure the choke closes all the way or nearly so and that it gets pulled open slightly as soon as the engine starts. With the electric choke it will usually open pretty fast, like within 3 min or so. You can adjust it to open a bit slower if need be. What you experience is actually pretty common on the older carbed inboards due to the lack of fast idle, which on a marine engine would be dangerous vs an auto appliction where you have brakes to slow you down. So it may be time for a general tune up and carb adjustment. I do alway warm up the engine before casting lines off. These carbed engines are not like EFI engines, they need a bit of warm up before a load is put on them so they don't stall.

While it has an electric choke, a marine inboard carb does not have a fast idle cam like it would in an automotive appliction, so after starting and putting it in gear there is no fast idle. This means that for it to not stall it has to be in near perfect tune and carb adjustment. Make sure the choke closes all the way or nearly so and that it gets pulled open slightly as soon as the engine starts. With the electric choke it will usually open pretty fast, like within 3 min or so. You can adjust it to open a bit slower if need be. What you experience is actually pretty common on the older carbed inboards due to the lack of fast idle, which on a marine engine would be dangerous vs an auto appliction where you have brakes to slow you down. So it may be time for a general tune up and carb adjustment. I do alway warm up the engine before casting lines off. These carbed engines are not like EFI engines, they need a bit of warm up before a load is put on them so they don't stall.

Thanks Lou! That's helpful. I understand it better now. So I turned the idle up to about 850 RPM in gear. It started and went into gear without stalling

 

[ggundersen3]

Thanks Lou! That's helpful. I understand it better now. So I turned the idle up to about 850 RPM in gear. It started and went into gear without stalling

Thanks again Lou. So I removed the flame arrestor and watched the electric choke open as you said. The choke is 95% closed when starting, but it does open gradually after that but maybe still too quickly. Its easy to adjust so I'll be aware of that. I'll turn down the idle to about 750RPM in gear as its slightly too high at 850. Thanks again for all your insight and info.

 

[Lou C]

Go for 600 rpm even with the cone clutch drive you have, lower is better.
And keep in mind those of us who learned to drive in the 60s and 70s are used to carbed engines and chokes. We were always tinkering with them to get them set up just right. My Quadrajet fires off quickly if the boat was used recently, if not it needs 2-3 crank overs to fill the float bowl because gas will evapoate over a couple of weeks. And remember carbed engines like warm up, especially marine ones that cannot use a fast idle cam set up. So start it, let it idle with the throttle set at 1500 rpm to warm up for a couple of minutes, then it should not stall at idle speed.

 

[ggundersen3]

H

Go for 600 rpm even with the cone clutch drive you have, lower is better.
And keep in mind those of us who learned to drive in the 60s and 70s are used to carbed engines and chokes. We were always tinkering with them to get them set up just right. My Quadrajet fires off quickly if the boat was used recently, if not it needs 2-3 crank overs to fill the float bowl because gas will evapoate over a couple of weeks. And remember carbed engines like warm up, especially marine ones that cannot use a fast idle cam set up. So start it, let it idle with the throttle set at 1500 rpm to warm up for a couple of minutes, then it should not stall at idle speed.

Lou,
Here's the latest, I had the boat out on the lake yesterday, I did everything you suggested. After letting it run at 1500 RPM for like 5 minutes, i brought it down to idle, shifted into gear and it stalled. It took about 5 tries to get it finally into gear without stalling. Should I try adjusting the electric choke slightly? I observed something else yesterday and this could be key, my temperature guage never even makes it near 120 degrees even when underway at higher rpm. It stays below the 120 deg marker on the guage. I noticed this last time I had this problem too. AND I recall the first time out this year when I had NO problem with this and it started and shifted into gear perfectly without stalling, the temperature came up rather quickly to 120 then 150 topping out at about 180 deg once underway at higher RPM. Is my thermostat stuck open and the engine is never heating up correctly? Is that the root of my problem?

 

[Lou C]

Well you probably have 2 problems:
Yes your thermostat might not be closing all the way, all it takes is a flake of rust or grain of sand. Common problem in raw water cooled engines. But even with a good stat these engines warm up slow and it should be able to run without stalling after like a 2-3 min warm up after the first start. So you can set the choke so it opens slower but just make sure it’s fully open after like 5-7 min of run time. If it still stalls you may need a general tune up (plugs, rotor & dist cap) and carb adjustment (fuel mixture). If that still doesn’t solve the problem it may be time for a carb cleaning and rebuild. I find I need to do that with my 4 bbl Quadrajet every 6 seasons or so. Before doing that though dump the contents of the large fuel filter out and see how it looks; I put it in a large Mason jar and let it sit. Layer of water or crud on the bottom?
Mine looks like this each year, clean. If you have water/crud at the bottom it may be time to clean out the tank.

 

[ggundersen3]

Well you probably have 2 problems:
Yes your thermostat might not be closing all the way, all it takes is a flake of rust or grain of sand. Common problem in raw water cooled engines. But even with a good stat these engines warm up slow and it should be able to run without stalling after like a 2-3 min warm up after the first start. So you can set the choke so it opens slower but just make sure it’s fully open after like 5-7 min of run time. If it still stalls you may need a general tune up (plugs, rotor & dist cap) and carb adjustment (fuel mixture). If that still doesn’t solve the problem it may be time for a carb cleaning and rebuild. I find I need to do that with my 4 bbl Quadrajet every 6 seasons or so. Before doing that though dump the contents of the large fuel filter out and see how it looks; I put it in a large Mason jar and let it sit. Layer of water or crud on the bottom?
Mine looks like this each year, clean. If you have water/crud at the bottom it may be time to clean out the tank.

Well you probably have 2 problems:
Yes your thermostat might not be closing all the way, all it takes is a flake of rust or grain of sand. Common problem in raw water cooled engines. But even with a good stat these engines warm up slow and it should be able to run without stalling after like a 2-3 min warm up after the first start. So you can set the choke so it opens slower but just make sure it’s fully open after like 5-7 min of run time. If it still stalls you may need a general tune up (plugs, rotor & dist cap) and carb adjustment (fuel mixture). If that still doesn’t solve the problem it may be time for a carb cleaning and rebuild. I find I need to do that with my 4 bbl Quadrajet every 6 seasons or so. Before doing that though dump the contents of the large fuel filter out and see how it looks; I put it in a large Mason jar and let it sit. Layer of water or crud on the bottom?
Mine looks like this each year, clean. If you have water/crud at the bottom it may be time to clean out the tank.

Thanks a lot Lou,
Is changing the thermostat fairly basic? Like removing the hoses that go into a thermostat housing on top of the engine, then removing the housing, then replacing the t-stat and re-assembling everything? I'd like to put a new t-stat in for sure as part of the solution to this issue.

 

[Lou C]

Yes it is held in by a rubber ring that may be obscured by rust. You need a thin screwdriver or pick to dig it out. Then use something like OMC gasket sealer, Merc perfect seal or Permatex Aviation sealer on the gasket and bolt threads.

 

[ggundersen3]

Yes it is held in by a rubber ring that may be obscured by rust. You need a thin screwdriver or pick to dig it out. Then use something like OMC gasket sealer, Merc perfect seal or Permatex Aviation sealer on the gasket and bolt threads.

Just a follow up to explain how this got resolved. I ended up taking it to a local dealer with 3 concerns, the stalling going into gear and not coming up to temperature issue and the water in the bilge(separate post). They found both problems. The sea water pump was leaking causing the water in the bilge and the previous owner REMOVED the thermostat entirely so the engine was running with NO thermostat and always running cold and never warming up. They replaced the sea water pump and also the thermostat and adjusted the idle to about 600RPM in gear. They also found a small amount of debris lodged in one of the hoses. So now it starts, warms up to correct temp in a few minutes, goes into gear smooth with no stalling and no water in bilge. I've had it on the water twice with no problems.
Thanks for all your help and info Lou and everybody!

 

[Lou C]

Great outcome glad the shop took care of it for you!