Everything done but low rpm at WOT. Distributor spring?

[jimmbo]

Jimmbo, that is Bnewton530 who said that (not me the original poster with this issue). Does not matter if I "mash" it or go gradual - no plane. I just bought a 4 blade prop online that has 2 inches less pitch. Will try that and report.

Sorry. I wish the Site, could provide an Identifier, for the OP, cause after many posts/replies I get confused. I will edit/delete the post

More Blade Area might help. Have you ever checked to see if the Exhaust Pipes are Clear? If the damn engine can't Exhale...

 

[VancouverBoat]

Sorry. I wish the Site, could provide an Identifier, for the OP, cause after many posts/replies I get confused. I will edit/delete the post

More Blade Area might help. Have you ever checked to see if the Exhaust Pipes are Clear? If the damn engine can't Exhale...

Thanks. Yes, exhaust is clear (just had exhaust manifolds off) and can easily get full revs in neutral.

 

[jimmbo]

Full revs in Neutral means Eff all. The engine is not under Load. It is a great way to throw a Rod, due to the very high G-loads suddenly imposed on the Rods and Pistons. Did you check the Y Pipes and the Exhaust Bellows?

 

[VancouverBoat]

Full revs in Neutral means Eff all. The engine is not under Load. It is a great way to throw a Rod, due to the very high G-loads suddenly imposed on the Rods and Pistons. Did you check the Y Pipes and the Exhaust Bellows?

Yes, I had the exhaust manifolds and risers/elbows off and was able to inspect inside the y pipe.

 

[Scott Danforth]

Drive all the way down for hole shot?

Trim tab location? Up, level with hull?, Down?

Something is seriously wrong

If the compression is as stated, WOT manifold vacuum under load is as you stated, accelerator pump works as stated, weight is as stated. a Ford 460 should move the boat along just fine

None of us are there to assist or trouble shoot.

Please verify everything

Compression numbers
Fuel pressure at WOT
Plug color
Timing
Firing order
Ignition advance at 3000 rpm
Exhaust system is clear
Boat weight
Drive trim
Trim tab location

 

[VancouverBoat]

Drive all the way down for hole shot?

Trim tab location? Up, level with hull?, Down?

Something is seriously wrong

If the compression is as stated, WOT manifold vacuum under load is as you stated, accelerator pump works as stated, weight is as stated. a Ford 460 should move the boat along just fine

None of us are there to assist or trouble shoot.

Please verify everything

Compression numbers
Fuel pressure at WOT
Plug color
Timing
Firing order
Ignition advance at 3000 rpm
Exhaust system is clear
Boat weight
Drive trim
Trim tab location

Drive all the way down for hole shot?

Trim tab location? Up, level with hull?, Down?

Something is seriously wrong

If the compression is as stated, WOT manifold vacuum under load is as you stated, accelerator pump works as stated, weight is as stated. a Ford 460 should move the boat along just fine

None of us are there to assist or trouble shoot.

Please verify everything

Compression numbers
Fuel pressure at WOT
Plug color
Timing
Firing order
Ignition advance at 3000 rpm
Exhaust system is clear
Boat weight
Drive trim
Trim tab location

Thanks, I am going through everything again. I rechecked the throttle linkage and noticed that the carb throttle arm was getting held back a bit by a tab on the intake manifold. I thought I had solved the issue. It did get me another maybe 400 rpm at WOT (now about 3500) but still not enough. The carb throttle is opening all the way to the stop. In regards to your points:
Compression numbers - 150 across
Fuel pressure at WOT - don't know but will buy gauge
Plug color - new
Timing - 12 BTC
Firing order - as per ford 460
Ignition advance at 3000 rpm - about 25
Exhaust system is clear - yes
Boat weight - perhaps 8400ilbs
Drive trim - down
Trim tab location - Up. Have used for trying to push bow down and get a plane but not getting there.

 

[jimmbo]

Timing - 12 BTC

Ignition advance at 3000 rpm - about 25

Boat weight - perhaps 8400ilbs

When you say Ignition Advance @3000rpm as 25. do you mean the Total Timing is 25 degrees, or the advance is 25 degrees for a Total of 37 degrees?

8400lbs, that is a lot of Boat. I wish I had my old Merc Accessory Catalogs, as they would give Hull Weights in the Prop Charts

 

[VancouverBoat]

When you say Ignition Advance @3000rpm as 25. do you mean the Total Timing is 25 degrees, or the advance is 25 degrees for a Total of 37 degrees?

8400lbs, that is a lot of Boat. I wish I had my old Merc Accessory Catalogs, as they would give Hull Weights in the Prop Charts

Total is about 37. Yes, it is not a light boat

 

[jimmbo]

So the Advance is coming in early enough.

I have had it for 2 summers and it has never achieved a plane. Had compression checked at 150 all cylinders. Since then, top end redone with new heads, plugs, wires, distributor. Rings/pistons were apparently ok. Timing chain and sprockets, camshaft were not changed. vacuum 14 at idle

14" inches is on the Low Side, but Back Pressure in the Exhaust might be a factor.
Any Idea on the # of Hours this engine has on it?
By your Name, I will assume you are in the Vancouver Area. Vancouver BC or Vancouver Washington? What altitude are you boating at? That will certainly affect the Vacuum Reading and the Engines Power

Edit: I'm starting to wonder if the Cam Timing is retarded. An old Chain can do that, but so can some low Quality Timing Sprockets, or improperly installed Aftermarket Sprockets that allow Advancing/Retarding of the Cam during Assembly. Since the history of the Engine prior to you owning it is more or less unknown

 

[VancouverBoat]

So the Advance is coming in early enough.

14" inches is on the Low Side, but Back Pressure in the Exhaust might be a factor.
Any Idea on the # of Hours this engine has on it?
By your Name, I will assume you are in the Vancouver Area. Vancouver BC or Vancouver Washington? What altitude are you boating at? That will certainly affect the Vacuum Reading and the Engines Power

Edit: I'm starting to wonder if the Cam Timing is retarded. An old Chain can do that, but so can some low Quality Timing Sprockets, or improperly installed Aftermarket Sprockets that allow Advancing/Retarding of the Cam during Assembly. Since the history of the Engine prior to you owning it is more or less unknown

I am in Vancouver BC boating in the ocean. No ideas on hrs, but only 50 since head rebuild. Engine does run very smooth. Could not plane when I got it. Compression was good then but still changed the heads as mechanic said we could check pistons and eliminate valve as an issue, and reduce oil consumption. The mechanic did not suggest doing camshaft, or doing timing chain. Would advancing the timing a bit help with that? Could cam lobes be flat? I saw a post https://forums.iboats.com/threads/omc-king-cobra-460.190188/page-2 where someone said that they had good compression but low WOT rpms because of flat lobes. Maybe I wasted my money just doing the heads. I do still have good compression but still fairly high oil consumption.

 

[jimmbo]

Welcome Fellow Canuk
When you mention "Advancing the Timing" I will assume you are referring to Cam Timing. If the Cam Timing is indeed retarded/late, advancing it will certainly help low end and mid range torque, and would likely raise the Intake Manifold Vacuum.
First thing would be to check for a Worn/Stretched Chain. Also check that the Sprocket Timing Marks still line up. However the only Accurate way to verify Cam Timing is to Degree the Cam. These Items are all best/easier done with the engine out of the boat. You should also measure the Lift.
Worn Lobes will certainly strangle an Engine as it can't Inhale.

Oil consumption. Most Oil burning is because of, not worn Rings, but worn Main and Rod Bearings. Worn Bearings leak a lot, and throw a lot of Oil around, and some gets on the Cylinder Walls and if too much, the Oil Control Rings are overloaded and can't scrape all of it off, and it gets into the Combustion Chamber.
Worn Valve Guides and worn/broken/missing Valve Guide Seals are also a source of Oil Burning.

Thing is. I, nor anyone on this Board, can see/touch your engine. All we can offer is Advice, based on our past Experiences, from the Symptoms you provide.

 

[VancouverBoat]

Welcome Fellow Canuk
When you mention "Advancing the Timing" I will assume you are referring to Cam Timing. If the Cam Timing is indeed retarded/late, advancing it will certainly help low end and mid range torque, and would likely raise the Intake Manifold Vacuum.
First thing would be to check for a Worn/Stretched Chain. Also check that the Sprocket Timing Marks still line up. However the only Accurate way to verify Cam Timing is to Degree the Cam. These Items are all best/easier done with the engine out of the boat. You should also measure the Lift.
Worn Lobes will certainly strangle an Engine as it can't Inhale.

Oil consumption. Most Oil burning is because of, not worn Rings, but worn Main and Rod Bearings. Worn Bearings leak a lot, and throw a lot of Oil around, and some gets on the Cylinder Walls and if too much, the Oil Control Rings are overloaded and can't scrape all of it off, and it gets into the Combustion Chamber.
Worn Valve Guides and worn/broken/missing Valve Guide Seals are also a source of Oil Burning.

Thing is. I, nor anyone on this Board, can see/touch your engine. All we can offer is Advice, based on our past Experiences, from the Symptoms you provide.

Thanks, I see you are in Edmonton?, Of course I am trying to solve the WOT issue without removing the engine from the boat, especially since I just did all the upper end work. I know the valve guides and seals are brand new. I suppose I can just be happy to run at 8 knots at 1800 rpm and still get to all the good places - just slower. It is annoying going under the 2nd narrows bridge doing 8 knots against a 7 knot tide current. I am still going to try the lower prop pitch and perhaps maybe a 750crm carb. Maybe I have to turf all the useless items I keep in the boat to reduce weight.

 

[jimmbo]

I always say to leave the Wife, Kids, and Mother-in-law, especially the MIL, ashore. Girlfriends and Mistresses, however are allowed aboard.
I don't think a bigger carb is going to fix it. You have an 1850 on there. Are the secondaries opening? I used to fit a clip to the Secondary Actuator Rod, loose enough to move but snug enough not to fall off, or slip. If the secondairies are not opening, the engine can't breathe.
Only time I was on the Water in a Small Boat, near Van, was in 1986, some friends of my friends took us up, I think it was called, Indian Arm, from Deep Cove, to the Twin Islands. I took a lot of good pics from that Island, but none are on the comp, just this one of Deep Cove. Never saw any boats going much more than Idle the entire Day.

 

[VancouverBoat]

I always say to leave the Wife, Kids, and Mother-in-law, especially the MIL, ashore. Girlfriends and Mistresses, however are allowed aboard.
I don't think a bigger carb is going to fix it. You have an 1850 on there. Are the secondaries opening? I used to fit a clip to the Secondary Actuator Rod, loose enough to move but snug enough not to fall off, or slip. If the secondairies are not opening, the engine can't breathe.
Only time I was on the Water in a Small Boat, near Van, was in 1986, some friends of my friends took us up, I think it was called, Indian Arm, from Deep Cove, to the Twin Islands. I took a lot of good pics from that Island, but none are on the comp, just this one of Deep Cove. Never saw any boats going much more than Idle the entire Day.

Nice pic with all those 80s boats. Indian Arm is where we go often. You might remember twin island from the attached pic. Anyways, I like your idea for dropping the weight. I did check the secondaries ( I was driving with friend looking - perhaps friend got it wrong) but should re-check. Do you mean to clip them open?

 

[jimmbo]

Just to see if the shaft was moving to open the Secondaries, I would place it where movement would cause it to slide down the Shaft, as the Actuator moved upwards.
Some quick scans from Prints. August 16, 1986.

 

[jimmbo]

Nice pic with all those 80s boats. Indian Arm is where we go often. You might remember twin island from the attached pic. Anyways, I like your idea for dropping the weight. I did check the secondaries ( I was driving with friend looking - perhaps friend got it wrong) but should re-check. Do you mean to clip them open?

It is so beautiful there, except for the Humidity. Last time I was in the Van Area was in 2015, I was in Richmond for a Convention. Met and photographed John Horgan there

 

[Scott Danforth]

what color are the plugs.

new isnt a color.

white, coffee, or black.

if your plugs are white, you are way way too lean.

measure the rocker arm movement with a dial indicator. your valves should be moving almost 0.550"

 

[Lou C]

sure, but I have checked everything in the list:
1. Fuel condition. Type and Octane possibly old fuel -
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.

That just leaves Carb and prop pitch. Prop is good condition and was the size sold with engine/boat so..... I guess a new carb...?

I’ll add one more thing to that list, anti siphon valve on the gas tank. That’s what stopped my boat from planing out. Then can corrode & the spring loaded ball gets stuck. Restricting fuel flow…

 

[Scott Danforth]

fuel pressure will point out the Anti-Siphon or pickup tube filter as issues if there is no fuel pressure at anything over idle.

 

[Lou C]