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82' 75hp Evinrude 3cyl not reaching full RPM when WOT

joereeves said:
I couldn't see the sealing surfaces of the block or head in the pictures close enough to tell if there were any corroded trails between the water passages and the cylinders. That would have needed to be determined by you. If those surfaces turned out that there was just one slight "dig" trail between the water passage and the cylinder, the head gasket would be unable to prevent water from flowing through it.

If on the other hand, those sealing surfaces were perfect, and you torqued the head bolts properly, the water would be entering the cylinder via another route.... normally via the gaskets in the exhaust baffle plate on the port side of the engine and/or a warped exhaust baffle plate. If you decide to go into that (usually necessitates powerhead removal), replace the inner baffle plate #324555 with a new one as it is a troublesome thickness and prone to warping.... avoid double/repeat work!
Click to expand...

Hey Joe,

i recevied. All new gaskets and will be putting them on tonight. I know I did not use sealant for the head gasket.

Do I use a sealant for the exhaust gaskets? What would u recommend. Can it be purchased from an auto store?

thanks again for all the help.
 
If the gaskets have a dry but glossy look to them, that would be a sealer that seals via engine heat... do not apply any sealant to them. They usually have a notice printed upon them too. Quite normal for cylinder head gaskets in today's world.

If the exhaust gaskets are plain gaskets with no glossy sealer on them, use regular gasket sealer that comes in a can that has a brush attached to its screw off cap, available at any auto parts store.

One area that one NEVER uses sealer on is gaskets that pertain to the fuel system... carburetor, intake manifold, etc.

(Gasket Sealers)
(Usually available at any reliable automotive parts type store)
(J. Reeves)


Do Not use any type of sealer on outboard carburetor or intake manifold gaskets as this would cause blockage of various fuel/air passageways. Also, there are new type gaskets, including head gaskets, which are used through out the engines that are coated with a substance that gives a shinny appearance to them. These gaskets are coated with a self sealer and are to be installed as is.... no sealers! Older style head and fuel related gaskets that are not coated with this substance are to be simply coated with oil.... nothing else.

All other gaskets (hopefully I've not overlooked anything above) should be coated with Gasket Sealer (the type that comes in a can that has a small brush in its screw off cap). This also pertains to some water pump installations that use a gasket between the plate and the lower unit housing.

Marprox Sealer 1000 or OMC Adhesive or Boat Armor Sealer 1000 (same substance)[See Below Note] should be used on any metal to metal (Unless GelSeal Is Called For) or metal to plastic surface (such as impeller hsg to plate, and plate to lower unit surface) to eliminate air leaks. It should also be used on the Spaghetti tubing that is used on many powerhead crankcase halves, lower unit skegs, etc. I have found that this substance works quite well on various "O" Rings such as what are found on lower unit carrier and upper driveshaft bearing housings (Note that this substance is obviously not to be used on all "O" Rings). This substance also works quite well in sealing the surfaces between the lower unit and the exhaust housing to which it attaches, eliminating the unsightly water spray between the two after completing a water pump installation.

NOTE 1: I am under the impression that Marprox Sealer 1000 and Boat Armor Sealer 1000 is no longer available.

NOTE 2: OMC Adhesive is now Bombardier 3M Product #847 and may be listed as Scotchgrip 847, part number 776964

DO NOT use any sealer on the large "O" Rings that are used on the upper and lower crankcase heads (The housing/heads that slide over the top and bottom of the crankshaft). On those "O" Rings, use only a coating of grease.

The exception of surface to surface contacts pertains to the later model matching crankcase (block) halves (which does not incorporate spaghetti tubing) which call for "Gel-Seal", or any other surface that calls for Gel-Seal. This substance seals in the absence of air, and if called for, must be used. One other form of Gel Seal that can be substituted is "Loctite #518". Nothing else that I know of will do!


I advise against using silicone or permatex on a outboard engine. It simply will not function properly. The exception to this (as per OMC's recommendation), is to use the black Permatex (heavily) on the gasket 306242 which seperates the inner exhaust tube from the exhaust housing on the 1959 35hp and 1960 to 1970 40hp OMC outboards.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************
 
joereeves said:
If the gaskets have a dry but glossy look to them, that would be a sealer that seals via engine heat... do not apply any sealant to them. They usually have a notice printed upon them too. Quite normal for cylinder head gaskets in today's world.

If the exhaust gaskets are plain gaskets with no glossy sealer on them, use regular gasket sealer that comes in a can that has a brush attached to its screw off cap, available at any auto parts store.

One area that one NEVER uses sealer on is gaskets that pertain to the fuel system... carburetor, intake manifold, etc.

(Gasket Sealers)
(Usually available at any reliable automotive parts type store)
(J. Reeves)


Do Not use any type of sealer on outboard carburetor or intake manifold gaskets as this would cause blockage of various fuel/air passageways. Also, there are new type gaskets, including head gaskets, which are used through out the engines that are coated with a substance that gives a shinny appearance to them. These gaskets are coated with a self sealer and are to be installed as is.... no sealers! Older style head and fuel related gaskets that are not coated with this substance are to be simply coated with oil.... nothing else.

All other gaskets (hopefully I've not overlooked anything above) should be coated with Gasket Sealer (the type that comes in a can that has a small brush in its screw off cap). This also pertains to some water pump installations that use a gasket between the plate and the lower unit housing.

Marprox Sealer 1000 or OMC Adhesive or Boat Armor Sealer 1000 (same substance)[See Below Note] should be used on any metal to metal (Unless GelSeal Is Called For) or metal to plastic surface (such as impeller hsg to plate, and plate to lower unit surface) to eliminate air leaks. It should also be used on the Spaghetti tubing that is used on many powerhead crankcase halves, lower unit skegs, etc. I have found that this substance works quite well on various "O" Rings such as what are found on lower unit carrier and upper driveshaft bearing housings (Note that this substance is obviously not to be used on all "O" Rings). This substance also works quite well in sealing the surfaces between the lower unit and the exhaust housing to which it attaches, eliminating the unsightly water spray between the two after completing a water pump installation.

NOTE 1: I am under the impression that Marprox Sealer 1000 and Boat Armor Sealer 1000 is no longer available.

NOTE 2: OMC Adhesive is now Bombardier 3M Product #847 and may be listed as Scotchgrip 847, part number 776964

DO NOT use any sealer on the large "O" Rings that are used on the upper and lower crankcase heads (The housing/heads that slide over the top and bottom of the crankshaft). On those "O" Rings, use only a coating of grease.

The exception of surface to surface contacts pertains to the later model matching crankcase (block) halves (which does not incorporate spaghetti tubing) which call for "Gel-Seal", or any other surface that calls for Gel-Seal. This substance seals in the absence of air, and if called for, must be used. One other form of Gel Seal that can be substituted is "Loctite #518". Nothing else that I know of will do!


I advise against using silicone or permatex on a outboard engine. It simply will not function properly. The exception to this (as per OMC's recommendation), is to use the black Permatex (heavily) on the gasket 306242 which seperates the inner exhaust tube from the exhaust housing on the 1959 35hp and 1960 to 1970 40hp OMC outboards.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay auction at:

http://shop.ebay.com/Joe_OMC32/m.html?_dmd=1&_ipg=50&_sop=12&_rdc=1
********************
Click to expand...


Update------ still no fix------ anymore help is very welcome!!!

so here is what I did and still no fix as far as power when under load:

rebuilt all 3 carbs
new head gasket
new spark plugs (plug1 was like new and had zero burn or what have you so I will check spark again on this cylinder)
new exhaust gaskets


It did solve the water in the middle cylinder which is good. But I get absolutely no power on the water. I can idle, and when WOT I bog out and kill it or it slowly comes up to 3000rpm for about 5mph.

any other suggestions?
 
If you now have proper compression and (with the spark plugs removed), spark that will jump a 7/16" gap with a strong blue lightning like flame...a real SNAP!, then normally that indicates a sticking timer base under the flywheel or/and a fouled carburetor(s).
 
Ok so to get to the timer base. Take off fly wheel nut, fly wheel, and stator.

Inspect to to see if there is build up, clean, then reassemble?

it looks fairly easy, I just wanted a little input on difficulty before I start taking it apart.
Thanks!
 
No need to dismantle anything to check for a sticking timer base. The timer base is connected to the vertical throttle arm via a goofy looking linkage that has plastic/nylon ball joints on its ends.

Simply observe that timer base closely while some slowly advances the throttle. It should advance and retard smoothly throughout its travel length.

You describe the top spark plug as the cylinder is not firing at all. However, you had good spark previously and that cylinder was firing.

Recheck the compression and the spark before doing anything else.
 
joereeves said:
No need to dismantle anything to check for a sticking timer base. The timer base is connected to the vertical throttle arm via a goofy looking linkage that has plastic/nylon ball joints on its ends.

Simply observe that timer base closely while some slowly advances the throttle. It should advance and retard smoothly throughout its travel length.

You describe the top spark plug as the cylinder is not firing at all. However, you had good spark previously and that cylinder was firing.

Recheck the compression and the spark before doing anything else.
Click to expand...

Ok was able to trouble shoot the missing spark. It was the coil. I will be taking the boat out tomorrow to see if that cleared it up. The coil I replaced had no reading when put on the voltmeter and it would not produce spark.

I will observe the timer base and see if it is sticking. Anything else to try while on the water if this does not work!?

thanks again for all the help.
 
Lazeronu said:
Ok was able to trouble shoot the missing spark. It was the coil. I will be taking the boat out tomorrow to see if that cleared it up. The coil I replaced had no reading when put on the voltmeter and it would not produce spark.

I will observe the timer base and see if it is sticking. Anything else to try while on the water if this does not work!?

thanks again for all the help.
Click to expand...


Update------ PROBLEM FIXED-------

so I hooked it up to the hose. I noticed now the TOP 2 cylinders were not firing (these were firing before I did all the work on the gaskets). I hooked a voltometer to all of them to measure each and compare. 1 was completely dead and the other was my receiving a ground. Replace and hooked up ground different.

Problem solved.


Total things done to solve:
replaced head gasket
replaces all exhaust gaskets (these both solved the water on the middle cylinder)
rebuilt all 3 carbs
checked ground and hot on all 3 coils
replaced dead coil
grounded unground coil
 
joereeves said:
No need to dismantle anything to check for a sticking timer base. The timer base is connected to the vertical throttle arm via a goofy looking linkage that has plastic/nylon ball joints on its ends.

Simply observe that timer base closely while some slowly advances the throttle. It should advance and retard smoothly throughout its travel length.

You describe the top spark plug as the cylinder is not firing at all. However, you had good spark previously and that cylinder was firing.

Recheck the compression and the spark before doing anything else.
Click to expand...

Hey Joe,


update and looking for a few more answers.

Took ok the boat out. Fires up, idles fine,

if if I increase throttle slowly I can go WOT and not bog down and die. If I try to go WOT off the get go it will bog out unless I throw it into neutral quickly.

If I slowly increase throttle I can get it to 2k rpms and it will then take off if I got Wot. After running at full throttle for a few minutes I can bring the boat to a stop, idle in neutral, throw it back in full throttle and it will have full power immediately.

I inspected all fuel lines for air leaks and have not found any. Pumping the fuel ball does nothing to increase able to take off.
All carbs were rebuilt and cleaned.

Could it be the fuel pump diaphram or the fuel/water filter?

Again any suggestions are greatly appreciated.
 
The hesitation when applying full throttle.........

Try pumping the fuel primer bulb up hard (acting as a manual fuel pump) just before hitting full throttle, filling the fuel system at the powerhead with fuel.

If that cures the problem, either a fuel/air leak exists somewhere between the fuel pump and the fuel supply... OR... the fuel pump is failing.
 
Last edited:
joereeves said:
The hesitation when applying full throttle.........

Try pumping the fuel primer bulb up hard (acting as a manual fuel pump) just before hitting full throttle, filling the fuel system at the powerhead with fuel.

If that cures the problem, either a fuel/air leak exists somewhere between the fuel pump and the fuel supply... OR... the fuel pump is failing.
Click to expand...

Hi again Joe,

Again all help is very much appreciated!

Ok its been a couple months. The problem still exists for the motor bogging down/dying when pushing the motor into WOT. Again, if I allow the motor to slowly build RPM it will take right off and run perfect at WOT. Its just when I floor it, it will die, if RPMs are not high enough.

I did try to pump the ball and act as a manual fuel pump, that did not help it at all.

One thing to note is after running WOT, I will throw in nuetral to slow down. The motor will rev to roughly 3k rpms and take 10-15 seconds to come back down to idling RPMs. Can this is part of the issue?

thanks for all the help.
 
The bogging down could be that the throttle butterflies are opening too soon in relation to the timing (link & sync) or one (or more) of the high speed jets are slightly clogged (running lean).

The butterflies must open and close at the same time... and just start to open when the scribe mark on the cam is aligned with the center of the 3/8" round throttle roller

And of course, a sticking time base will do that but you've already looked at that.

If the idle timing is not correct (link & sync).... 2,3,4 degrees, whatever the service manual says via the adjustable distance between the vertical throttle lever and the metal cam... that throws everything off and weird things will happen.
 
joereeves said:
The bogging down could be that the throttle butterflies are opening too soon in relation to the timing (link & sync) or one (or more) of the high speed jets are slightly clogged (running lean).

The butterflies must open and close at the same time... and just start to open when the scribe mark on the cam is aligned with the center of the 3/8" round throttle roller

And of course, a sticking time base will do that but you've already looked at that.

If the idle timing is not correct (link & sync).... 2,3,4 degrees, whatever the service manual says via the adjustable distance between the vertical throttle lever and the metal cam... that throws everything off and weird things will happen.
Click to expand...


Hey Joe,

I had a question. There are two scribes on the cam. One that has start written beside it, then below it another. Should the cam roller be aligned with the top Start scribe or the lower scribe? It is currently touching the Start scribe when in neutral.

thanks!
 
joereeves said:
The bogging down could be that the throttle butterflies are opening too soon in relation to the timing (link & sync) or one (or more) of the high speed jets are slightly clogged (running lean).

The butterflies must open and close at the same time... and just start to open when the scribe mark on the cam is aligned with the center of the 3/8" round throttle roller

And of course, a sticking time base will do that but you've already looked at that.

If the idle timing is not correct (link & sync).... 2,3,4 degrees, whatever the service manual says via the adjustable distance between the vertical throttle lever and the metal cam... that throws everything off and weird things will happen.
Click to expand...

ok so I was attempting to sync it tonight when I noticed a few things.

First thing was the WOT screw did not get close to touching at WOT. Neither did the idle screw. They were both halfway screwed in.

Second when setting the roller to the cam scribe mark, I could not get WOT to move the carbs all the way horizontal. It moved to 45degree or less.

is there an adjustment I am missing to allow me to advance the cam further? Could it be the throttle cable? If so how do I adjust it? I tried moving the wheel but it either increase the cam too far and I could not align the roller, or it would decrease it so much that when I aligned the roller, the cam would not advance far enough to open up the butterflies on the carbs.

As always any help is greatly appreciated!!
 
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