1988 Evinrude 90hp idle stalling and link n sync

[Lukeowski]

Ok here's the deal.
Acquired this boat in January, and It was stored outside for what the seller said was 1-2 yrs. Evinrude model TLCCA. I did a tune up with new water pump kit, carb kits, new plugs, wires, fuel primer, filter, water seperator. The compression readings I got were somewhere around 60 - 55 psi in ALL cylinders before I ever took it to the lake. Yes, that sound low, but it did run very well when I got it out on the water

A couple months later, it starts to become more apparent that the motor doesn't want to stay started and I have to jump into gear. It got to a point where it just wouldnt stay started in idle.

Ended up getting new aluminum float bowls and tapping out the intermediate orifice for the original jets. The old bowl were leaking and I was loosing fuel pressure. The previous owner did mention something about a power pack so I bought one only because a couple primary wires were freyed. I haven't checked the spark gap but my neighbor did have a timing light that I used to check for misfires. It appears that cylinder 2 was misfiring but my neighbor said it could be the result of a choke solinoid affecting the timing and that it went to normal after warming up and switching plugs around. Ignition coil ohm readings were all consistent as well. The motor as is will run on muffs. On the lake ramp/dock the motor stalls when the throttle arm goes down.

Here is the thing, I don't have the special tools to determine the timing specs, and the clymers manual I got doesn't have enough specific information to grasp the mechanism driving the throttle linkage.

It may be helpful for me to differentiate the mechanisms within the throttle itself so I can know better what I am adjusting.

What I do know is:
A. Carb plate has a ROLLER on it
B. ROLLER comes in contact with a CAM? The CAM has a mark to be set center of (A. Carb ROLLER).
C. THROTTLE CABLE is attached to a THROTTLE PLATE which actuates the TIMING ROD and an adjustable link to the CAM.
D. There is also a screw on top for (idle advance?)

What I don't know is what does the adjustable link between the cam and throttle plate do?

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From what I have read into, the roller needs to be set center of cam mark when it makes contact, and just after the timing arm moves.
And for what it's worth, the motor is marked at 28° BTC for previous owner/ mechanic I presume.

I will try to attach a picture for more the best understanding achievable since the clymers manual neglected to do so.

 

[ct1762@gmail.com]

the timing is set at idle with the cam roller exactly center with the 1st mark on throttle cam. from the pic, you have the idle speed screw way too far out. if it's stalling like that, and the roller is center of mark, somethings wrong with the internals. i'd take off both cylinder heads with reading that low... is your gauge accurate? the only tools you need to do link n synch are the FACTORY service manual (correct for the year- yours is 1988) a screwdriver, and a timing light. Dont have the specs, but its somewhere between 2 and 4 degrees BTDC i believe, but that number is just a starting point as when you set the idle in gear in the water with no throttle cable attached, it will change the timing a bit. I suspect scored pistons or 2.

 

[flyingscott]

Before you do anything get a different compression tester. Have you done a proper spark test. You do not care about idle timing that takes care of itself. What do.you mean you tapped out the intermediate orifice?? The choke does not effect spark at all!!!! And your motor does.not even have a choke!!! Get the correct factory factory manual for your motor. Stop doing anything until that arrives

 

[racerone]

I would be removing the cylinder heads to inspect cylinder walls.

 

[Lukeowski]

I will get another compression tester. I used the same one as I did before and no change in numbers from the first time.
When I get another compression tester I will get a spark gap tool as well.
If there is no choke thats fine, but there seemed to be some missing going on when I was running the motor with the timing light. So that may be part of the problem, but I let my neighbor convince me that there was a timing advance choke solinoid for initial start up or something along those lines...anyways, yes the new aluminum float bowls come with different size thread pitch for the intermediate orifice. I used the original orifice from the old float bowl because I could not find a new replacement orifice with the matching thread pitch for the new bowl.

It is next to impossible to find the factory service manual for this motor. Although diyrepairmanual.com claims they have one for a whopping 149 bucks. Not sure if I trust that.

 

[racerone]

Fact----Your neighbor was wrong !!----Should not be hard to find a manual for that motor.------88 / 90 / 100 / 110 / 115 HP were basically the same year after year from about 1980 to 1998 model years.

 

[flyingscott]

https://www.outboardbooks.com they have them. Ditch the Seloc and maybe the neighbor.

 

[jakedaawg]

I agree with the above. I would like to add this: the roller in the slot on the cam appears to be having an issue. Looks like someone may have replaced it with metal? If so it will wear out that cast cam. They are two parts with a black plastic inner and a translucent rubber like outer layer.

find the primer solenoid. It has a red lever. Make sure the red lever is in line with the solenoid body.

you should not have had to tap the new bowls, you should have bought new jets of the proper pitch and orifice size. Orifices may now be leaking around the threads. Might work just fine, but when all else is proven right and it still doesnt run right it will be something to ponder. Sealant wont work. I doubt you could get teflon tape on them also and not have it block the passage while screwing them in.

1st things 1st though. Either get a good name brand comp tester or take the heads off. Preferably both. Post results. Snap on, mac tools, the old craftsman professional were american made not sure nowadays, worth their price. The chinesium ones do not work, ever.

2nd is the open air gap spark test with appropriate tester. I like the Steven's instruments model as you can test all 4 holes at once and observe nice even times spark across all holes.

3rd, if you pass those two tests, drop the dimes on a factory manual. We wont be much help if you dont have one.

 

[Lukeowski]

The roller in the slot cam only looks like that because I put some grease in there.
Yes the primer solenoid lever is in line,not perpendicular.
I wish I didn't have to tap the bowl but other people have suggested that exact procedure in the same scenario with no issues. Maybe I could have found same sized orifice, but it's a tricky thing when they upgrade the bowl and you can't find new orifice to match the new bowl pitch and then used retailers don't specify what the thread pitch is for what they are selling.
The compression tester I was using is my dad's old Sears.
For what it's worth I do have a little video I took for whatever reason and it shows the #3 cylinder wall.
https://youtu.be/rjwfeGbaekk

 

[havoc_squad]

Maybe I could have found same sized orifice, but it's a tricky thing when they upgrade the bowl and you can't find new orifice to match the new bowl pitch and then used retailers don't specify what the thread pitch is for what they are selling.

An orifice size chart is provided in the factory service manual. It includes the pitch/thread of what exists. I don't know if this covers the plastic versus metal orifices, but its helpful info to have if you are having to figure out jets.

The problem is one has to have the previous knowledge that the plastic carb bowl for those similar series was similar in design except for the intermediate orfices, and one had to look up the part number of the same orifice to the older metal carb.

How I found out, I did some detailed research because I did not know these details. One cannot find answers like this if you only spend 30 minutes doing a light web search and give up.

When the replacement model of carb bottom was made the metal one, they never updated the parts diagram listing of this on the year models with the plastic bowls.

Why, I can't say. What I can say is someone who works on these motors on a regular basis knows the models 1981 to 1987 (1987 had a mixed year of metal/plastic), and 1995 up to 1998 uses the metal carbs. Or at least they have a clue about this in general.
.
Look up these motors and you will see the intermediate orfice: No#26 for a standard orfice: part number 0324652 for the 88/90 HP motor.

The 26C orifice is for the plastic carb bowls, which is discontinued.

Don't take my word for it, look it up yourself across those year models.

 

[ct1762@gmail.com]

Umm no offense but that video is useless. Can't see anything and there are 3 other cylinders to worry about:lol:

 

[Lukeowski]

Havoc_squad you are right about that I will eventually just order new orifice once I get through the main issue.

That being said, the main issue may be the carburetors for all I know.

Question: Is it common to remove and reinstall Welch plugs when doing a carb rebuild? I did not.

I got a speak gap tester and a compression gauge from the auto store.
The spark checks out with a blue 7/16 snap.
The new compression gauge is reading much higher at 110,105,110,110.

Something I noticed before when running the motor on muffs without the airbox off. Is the fourth cylinder was sneezing out the mouth of the carb. From what I've read about that indicates an issue with the reeds. Could there be a leak in the carb to manifold gasket?

 

[Lukeowski]

Update 6/28/20
After taking off the carbs to double check everything I found something lodged in the bottom 4th cylinder reed valve!! It was an old plastic hose clamp that had broke in half. How it got in there is a mystery, but I took the boat to the lake yesterday and it definitely ran better. And no more spitting from the bottom carb.
It was staying in idle a lot longer after warming up a bit, but I really didn't run the motor too much. A couple half mile trips to and from a fishing spot.
I will be adjusting the timing per factory service manual, that someone graciously posted online.
Since I don't own a test prop, I am going to attempt the Joe Reeves method.
I'll update again after that.
Thanks everyone!!