Frustrated! Won't rev up, 5.8L, been working on it a while!

[fireicyhott]

Hi guys,

I am getting frustrated. I have a 1990 Four Winns 225 Sundowner with a 5.8L OMC with Cobra outdrive. Boat only has 290 hours on it.

What it is doing is it won't go over like 2000rpms. When you give it more gas it bogs down, almost sounds like it is a vacuum leak.

Here is what I have done so far:

New plugs, look good
New distributor cap, wires, rotor, points (gapped correctly)
Timing is dead on
Just had Holley 4 barrel rebuilt with new kit.
Has new gas (high test)
New engine oil
Outdrive oil is fine
Not overheating
Prop is in good shape, 15x17

According to my uncle last year boat ran fine. He put it up last year not winterizing it (mistake) but I have done everything I know to do other than pay a mechanic to come out on lake with me. I thought getting carb rebuilt would solve problem, had to be done as I think there were issues with it.

Doesn't matter whether it is in gear and running or in neutral, won't rev over like 2K rpms.

HELP!!!!!!!!!!! Any ideas?

Thanks, Jeff in Shelby NC, not far from Charlotte

 

[45Auto]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Did the bogging start before or after the carb was rebuilt?

 

[MikDee]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Is your mechanical advance working on the distributor? not sure of your distributor rotation, but with the engine off, can you rotate the rotor one way, or another, by hand? I think it should rotate some to the right. Also, check your firing order, should be 18436572, then make sure your plug wires are not crossed, from front of engine right side should be 1,3,5,7, and left side should be 2,4,6,8

 

[Boatsrneat]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Its gotta be a fuel/carb issue. Automatic choke? check that is not stuck closed, or check that its closing when its cold? When it was rebuild, was the float level/ fuel bowl level adj. correctly. Things like this will make it run terrible.

Steve

 

[Haut Medoc]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Hi guys,

I am getting frustrated. I have a 1990 Four Winns 225 Sundowner with a 5.8L OMC with Cobra outdrive. Boat only has 290 hours on it.

What it is doing is it won't go over like 2000rpms. When you give it more gas it bogs down, almost sounds like it is a vacuum leak.

Here is what I have done so far:

New plugs, look good
New distributor cap, wires, rotor, points (gapped correctly)
Timing is dead on
Just had Holley 4 barrel rebuilt with new kit.
Has new gas (high test)
New engine oil
Outdrive oil is fine
Not overheating
Prop is in good shape, 15x17

According to my uncle last year boat ran fine. He put it up last year not winterizing it (mistake) but I have done everything I know to do other than pay a mechanic to come out on lake with me. I thought getting carb rebuilt would solve problem, had to be done as I think there were issues with it.

Doesn't matter whether it is in gear and running or in neutral, won't rev over like 2K rpms.

HELP!!!!!!!!!!! Any ideas?

Thanks, Jeff in Shelby NC, not far from Charlotte

1)....Get a timing light with the advance feature & check to see if it is advancing......
2) Get a vacuum tester & check to see what the reading is.....
3).....Hook up a six gallon aux tank & see if it helps......
Better yet, perform a fuel pressure & vacuum test as outlined by Don S. in the 'search' function...
4) I am not an OMC guy, but the ESA & it's components act very much like a shift interrupt switch on a Merc......
It will kill half of the cylinders if it thinks it is shifting.....
That will lose ya 2,000 RPM's real qiuck.....
The fact that it will not get WOT with no load suggests a timing/spark problem, IMHO.....
That should actually be #1 on the list........

 

[fireicyhott]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

How do I check if the mechanical advance is working?

I will double check the plug wires but I am 99.9% sure I put them back on correctly.

The distributor rotates counter clockwise I believe. I have been using a standard timing light. Should I be able to see the timing advance with the light when I rev the motor while in neutral?

Thanks for all the advice. It sure does seem like maybe the timing advance. It idles so good and runs great up to about 1800-2000K rpm and then just won't go higher than that.

Also, I have the kit to convert this to electronic ignition and get rid of the points. Would this do anything to help with the problem if it is timing advance? I really don't want to change this right now and add another variable to this equation.

Yes it did do this before the carb rebuild.

Thanks,

Jeff

 

[Bondo]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Should I be able to see the timing advance with the light when I rev the motor while in neutral?

Ayuh,....... You Should be able too......

Another thing that could cause your Issue is a Restricted Exhaust.....
Have you had an Over Heat lately,.....
Fried Flappers can fall into the exhaust system,+ cause this......

 

[rodbolt]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

if you use 18436572 on a 5.8 your gonna have backfire issues
the 5.8 ford used 2 different firing orders and usually its cast on the intake. if the casting is ground off you have the oddball one . just a ford thing from a fuzzy memory.
the ESA is simple to check, simply take it out of the system and run it,be aware it wont shift out of gear with the ESA,if used, out of the system.
I would install a fuel vacum guage on the fuel pump inlet, you should see about1"Hg and no more than 4"Hg. less and you may have an air leak. more and you have a fuel restriction. you may also wish to use the same guage and test fuel pump pressure.
normally if its a timing or ign issue it will miss and shake not run smoothly and bog.
break the engine into its subsystems and confirm or eliminate each. a restricted exhaust can be found with that same vacum guage you used to look for a fuel restriction.

 

[MikDee]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

OHNO! Whoops, Sorry about that, I was wrong, I thought it was a Chevy motor! That's the firing order I gave you. I don't have the Ford memorized? but did you try moving the rotor by hand to see if the advance springs, & weights in the distrbutor are working? With points as you said I'm guessing it's not electronic spark advance.

Yes, the Ford had 2 different firing orders, one was for a Windsor motor, the other for a Cleveland motor, the Windsor is more popular

 

[fireicyhott]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

I am headed to the dock this morning to check the mechanical springs, weights, etc. on the advance mechanism.

I have a set of mercury vacuum sticks I use on my motorcycle to check vacuum while setting fuel/air mixture. I wonder if can use one of the 4 tubes as a vacuum gauge on boat. If not I will buy one to check as "rodbolt" suggests.

Keep the suggestions coming.

Thanks,

Jeff

 

[MikDee]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

How do I check if the mechanical advance is working?

I will double check the plug wires but I am 99.9% sure I put them back on correctly.

The distributor rotates counter clockwise I believe. I have been using a standard timing light. Should I be able to see the timing advance with the light when I rev the motor while in neutral?

Thanks for all the advice. It sure does seem like maybe the timing advance. It idles so good and runs great up to about 1800-2000K rpm and then just won't go higher than that.

Also, I have the kit to convert this to electronic ignition and get rid of the points. Would this do anything to help with the problem if it is timing advance? I really don't want to change this right now and add another variable to this equation.

Yes it did do this before the carb rebuild.

Thanks,

Jeff

Yes, you should be able to see the timing advance move with your timing light, if the engine runs smooth, and you had this issue previously I suspect the timing advance, if it were carburetion, it would run rough, or backfire if too lean. By the way, the OMC has a shift interrupt switch that might be an issue with the electronic (Pertronics point's eliminator) I wouldn't mess with it at this time.

 

[rodbolt]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

like I say, they used 2 different firing orders.
some of the SVO engines used a different cam and crank so they grind off the fireing order thats cast in the intake.
thats why you can find the cleveland fireing order on a windsor motor, could be the reverse,memory gets fuzzy.
however to get back to your issue, ran fine,stored improperly now it wont run fine. usually something died in the fuel system.
after testing the compression I would start looking for water in the fuel or possibly a cracked riser/manifold allowing water into the manifold.
just sitting ign timing wont change, the advace weights can stick but thats easy to check. mark the balancer at the position its supposed to full advance to and spin the engine about 3000 RPM and see if it advances.
it should start advanceing by about 1100 or so.
and full advance about 2800.
if it actually ran well before sitting odds are the fuel system took a hit, its also posible that animals/insects have built a nest in the exhaust.

 

[fireicyhott]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

It has new fuel/water seperator, new gas, carb freshly rebuilt with kit.

How do I check for water in manifold and animal nest in exhaust? I can see exhaust bellow with boat on trailer and outdrive all the way up.

 

[Don S]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Just having a new filter and new gas and a rebuilt carb does not mean the fuel system is fine.
Run this test and see what you have,
http://forums.iboats.com/showthread.php?t=167561

List of possible causes of low WOT.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation (Full tuneup done recently)
• Remote control cables and linkage for proper travel to open throttle plates fully.

 

[Don S]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

One other thing you might check is the timing marks on your engine. I THINK the 351's had timing marks on both the BEFORE and AFTER side of TDC on the harmonic balancer. Make sure you set your timing on the Before side of the mark, not the after, or you will be 20? off.

 

[Haut Medoc]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Well, I see ya got some more really good input.....
For some reason I thought you said it ran crappy at all RPM's & would not go over 2000.....
Hence my ESA advice......
Anyway, the firing order should be 1-3-7-2-6-5-4-8......
I'm assuming that you were smart & changed the wires 1 at a time.......
Don & Rodbolt, both bring up some good points.......
I would think that you would have to have a really serious exhaust restriction for it to have that much effect with no load.....
You check for water in the exhaust by running the engine & pulling the plugs & spinning the engine.....
If you have a leak on one side, the water could have easily seeped past the rings over the winter....
Hopefully, you printed this thread & took it with ya to the dock......
Everyone of the tests will either confirm or rule out specific problems, ya just gotta do 'em all.......​

 

[fireicyhott]

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

Thanks for all the great info guys.

I spent about 8 hrs working on the boat today, trying something, taking it out, trying something else, taking it out, etc.

Long story short, ended up regapping plugs and it helped a lot. This was a suggestion of a mechanice friend, I had gapped them to .018 liked book said but I think I was too wide. He suggested using a crisp dollar bill.

Boat runs faster than before but still not there yet. Put new plugs in again,(last time was before carb was rebuilt). Still can't get more than about 3000K rpm and 28mph under load. It will rev higher without load.

Also there is some backfiring through carb (lean), fuel?

I will check the fuel issues that Don and the guys posted the link to. I will pull the vent tube and check screen in tank.

It wants to take off and run but isn't quite there yet. I will get it just have to have patience and take one thing at a time. Those damn points are for the birds!

Any other suggestions will be appreciated and I will keep you up to date.

Runs better but damn I'm tired and sunburned and dehdrated!

Thanks,

Jeff

 

[Haut Medoc]

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

Thanks for all the great info guys.

I spent about 8 hrs working on the boat today, trying something, taking it out, trying something else, taking it out, etc.

Long story short, ended up regapping plugs and it helped a lot. This was a suggestion of a mechanice friend, I had gapped them to .018 liked book said but I think I was too wide. He suggested using a crisp dollar bill.

Boat runs faster than before but still not there yet. Put new plugs in again,(last time was before carb was rebuilt). Still can't get more than about 3000K rpm and 28mph under load. It will rev higher without load.

Also there is some backfiring through carb (lean), fuel?

I will check the fuel issues that Don and the guys posted the link to. I will pull the vent tube and check screen in tank.

It wants to take off and run but isn't quite there yet. I will get it just have to have patience and take one thing at a time. Those damn points are for the birds!

Any other suggestions will be appreciated and I will keep you up to date.

Runs better but damn I'm tired and sunburned and dehdrated!

Thanks,

Jeff

The plugs should be @ .30......
The points should be @.18.....

 

[Don S]

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

Re: Frustrated! Won't rev up, 5.8L, UPDATE: 8 HRS WORKING!

I think you are doing a lot of work for nothing. I never once mentioned pulling the vent tube or pickup tube or anything else. I did (in the other thread) say to put a gauge on the fuel system and check it. The gauge will tell you things you can't see. YOu might see a plugged screen, but not an air leak around a fitting, hose, or __________ (fill in the blank) and an air leak is a serious possibility.
Also, as haut mentioned, .018 is the gap for the points, not the spark plugs, and is used only to get the engine running so you can check and reset the dwell with a dwell meter. Setting the gap is fine if you are really good at it, but it doesn't sound that way to me. Then after setting the dwell you MUST reset the timing, cause dwell effects timing. Then you need to check your advance timing

 

[fireicyhott]

Re: Frustrated! Won't rev up, 5.8L, been working on it a while!

Don,

Thanks again for the advice. I typed that wrong and meant to say I regapped the points, not the plugs. Plugs are new as of yesterday and are at .030.

I have printed off the fuel system checklist and will take it with me tonight. I will pull the vent hose to see if it is clogged and the fuel pickup hose to see if the screen is blocked. I sure do hope it is one of these that is the problem.

Mechanical advance on distributor seems to work fine.

Question, I know when I first got the boat I had to suck the old gas out of the tank and I had to take off the round cover on the top of the tank that holds the float. This was the only hole big enough to get my hose down in to suck it out. If I didn't get that selaed and tight when I put that cover back could it cause an issue? Fuel gauge is reading 3/4 full when tank is slam full so maybe my float needs adjustment (least of my worries).

I don't have a gauge to check fuel system but will see about getting one.

Thanks,

Jeff