1988 Mercury 60 hp loss of power / acceleration

[bradbettes]

I have had this engine for about 4 months and I just can't get it to running right. Since I am fairly new to boat engines, let me kinda give you my history with this engine.

I took the boat out about a week after I bought it and like a moron, ran it out of gas. Before it ran out of gas, it ran fine, pushed the boat at about 27 mph, according to GPS. A week or two later, I filled the tank and took it to Toledo Bend. Ran fine for a minute or two, then started bogging down upon acceleration. It got to the point that it would die whenever I even put it in gear and tried to accelerate, regardless of the rate of acceleration.

At this point, I realized I had an issue and began looking at the fuel system as the culprit. I searched this and many other sites for information and have done quite a bit to try and get it running to no avail.

Things I have done so far:
Replaced fuel line
Rebuilt fuel pump
Rebuilt carb after soaking in Chem-Dip
Installed new fuel filter in engine along with inline filter in fuel line
Adjusted needles on front of carb today to try and get it running better (can't remember what they're called)

Current status of engine:
Engine will start fairly easily
Idles fine
When engine is accelerated slowly, with pick up smoothly through about 3/4 throttle, then it sputters
When throttle is hammered, engine sputters immediately and dies 99% of time unless you let off throttle

I did the carb adjustments with boat backed into water but still on trailer. I also noticed that the gasket on the bolt at the bottom of carb was leaking when I was initially adjusting, but I had another one that I was able to replace it with. However, I had to remove and replace the bolt with needle nose pliers so I wasn't able to get the bolt back in as tight as it probably should be.

I am really at a loss right now as to what to do, so any help would be appreciated. If I am leaving out any information, just ask.

Thanks in advance,
Brad

 

[kcsolovely]

Re: 1988 Mercury 60 hp loss of power / acceleration

I have a 1989 Merc. 100 and it has a simlar problem except at full throtel it runs high with out any increase of speed. It did have problems not starting i used full stablizer from the Sea Ray dealer no problem starting. It runs fine until I encrease the throtle how ever it just get loud with out the speed increase. I fill your pain my guess is carb needs a good cleaning

 

[dradford78]

Re: 1988 Mercury 60 hp loss of power / acceleration

You said that you did the carb adjustments. Did you do the high speed adjustment also.

 

[bradbettes]

Re: 1988 Mercury 60 hp loss of power / acceleration

You said that you did the carb adjustments. Did you do the high speed adjustment also.

I'm not real sure what you mean by "high speed adjustment" - please elaborate, because I am pretty sure I did not do anything "high speed" .

Brad

Edit:
I found the thread that contains the directions that I tried to follow on the lake: http://forums.iboats.com/showthread.php?t=286239
Keep in mind that I found this thread a month or so ago and had a pretty good understanding of it when I went to the lake, but unfortunately due to what I like to call technical difficulties, I did not have the instructions with me on the boat.

I backed the boat down the ramp and kept in on the trailer. I cranked the engine and then began to adjust the screw on the right side of the face of the carbs about 1/8 to 1/4 of a turn at a time starting from 1 1/2 turns out. While adjusting I was mainly backing out from that 1 1/2 turn initial setting. I could definitely tell a difference in how the engine was idling while adjusting, but am not sure what exactly I was looking for. I did notice at one point that idle speed was around 1000 rpm in neutral.

I am going to try the adjustment procedures explained in that thread again, this time with the actual procedures on the boat with me.

Is there an initial setting that I should be going with to begin my adjustments?

Is there a certain idle rpm that I should be shooting for, both in gear and out?

Should I put the boat completely in the water or is leaving it trailered ok? The main reason I left it trailered was in case I completely screwed something up and couldn't get it loaded back up (the trolling motor is not that great to load with in high winds - trust me, I know).

Brad

 

[Faztbullet]

Re: 1988 Mercury 60 hp loss of power / acceleration

You have no high speed adjustment as the these are fixed jets in fuel bowl. Have you done a sync & link on carbs/linkage since you had them off? Do you have the factory manual?

 

[bradbettes]

Re: 1988 Mercury 60 hp loss of power / acceleration

You have no high speed adjustment as the these are fixed jets in fuel bowl. Have you done a sync & link on carbs/linkage since you had them off? Do you have the factory manual?

I don't know what a sync & link is to be honest. No, unfortunately I don't have the factory manual, which is kind of amazing since it seems I have a manual for everything else I own.

 

[Faztbullet]

Re: 1988 Mercury 60 hp loss of power / acceleration

Try this....
http://www.tradebit.com/filedetail.php/127576820-mercury-download-1965-1989-outboard-service-manual

 

[bradbettes]

Re: 1988 Mercury 60 hp loss of power / acceleration

I got the manual for my motor and got to work on it yesterday evening. I set the initial timing and max advance and then played with the carb needles to get it to running. I will say that the motor is running a lot better, but it still has some issues. Now that I have more refined info and I understand the motor a little more, I thought I would post up here and offer a better view of how the motor is set up right now.

Throttle stop is set so that it stops throttle cam just as carb is reaching its own stop.

Max advance spark stop is set to the "MAX ADVANCE" mark on timing wheel when throttle cam is just reaching the secondary pickup. (I assume this to be 28 degrees BTDC at cranking rpm's giving me 23 degrees BTDC at 5300 rpm's.

Primary pickup spark stop is set to 8 degrees BTDC.

Idle stop is set to idle right under 1000 rpm's. (I can't seem to keep it steady and have it shift into gear without dying at much less than this.)

Top carb needle is turned out 3.5 turns from snug.

Bottom carb needle is turned out 3 turns from snug.

When adjusting carb needles, it found that I had to screw the needle pretty much all the way in before it would stumble. I never could get it to stumble by turning it out. All initial carb adjustments were done with boat in water and motor in neutral. I ended up bringing the carb needles all the way out to their current position while trying to get a hole shot. Any less and the motor dies while trying to accelerate. While adjusting carb needles, I also had to adjust idle stop to keep the idle speed within a reasonable range. However, this resulted in the idle stop being positioned so that the throttle cam is almost to the secondary pickup. (I am thinking this can't be right.)

As it stands right now, the engine will fire up fairly easily, idles about 1000 or a little less, shifts into gear and idles, has moderate power upon rapid acceleration. The issue that I am having now is that the motor will not go over 2000 rpm's at WOT. Also, I have a lot more power with the motor trimmed up; with it down, it seems like it wants to bog a little (I assume this is due to less back pressure).

I am really not sure where to go from here. I don't know if the adjustments I made are what is causing this or if there is something else I need to look at. At the very least, I am learning about boat motors lol.

 

[PHE]

Re: 1988 Mercury 60 hp loss of power / acceleration

When you cleaned the carbs, did you remove the main jets, squirt some carb cleanner through them and make sure they didn't have any dirt in them? Did youthen squirt carb cleaner through all the little ports, particularly the idle circuits?

Are you getting fire on all cylinders?

You should keep all the carbs adjusted the same. Not sure about this motor, but many require a very rich idle adjustment to provide enough fuel to get it out of the hole. Having said that, three turns out sounds like a lot.

You should keep the carbs all adjusted the same.

Not sure I understand your timing adjustments. Mine is adjusted at full throttle while cranking the engine with the plugs out, connected to the plug wires, and with a wire grounding the plug body to the engine. Did you follow the procedure in the manual?

If you don't have a manual, you should buy one. You will need it.

 

[PHE]

Re: 1988 Mercury 60 hp loss of power / acceleration

You should also look at this article in the engine FAQ: http://forums.iboats.com/showthread.php?t=168855

 

[bradbettes]

Re: 1988 Mercury 60 hp loss of power / acceleration

You should also look at this article in the engine FAQ: http://forums.iboats.com/showthread.php?t=168855

PHE,
I do have a manual but got a little confused when trying to follow the procedures in it. The above article is exactly what I followed when
doing the adjustments. As far as the cleaning of the carbs goes, I pulled them apart and soaked them in carb cleaner overnight, then I used my air compressor and blew everything out of every orifice that I could find. I have also replaced the needles and everything when I rebuilt the carbs. I am not sure I am getting fire on all cylinders, I am planning on checking that, just not exactly sure how to since I don't have a spark tester. Also, I was just looking at the plug wires on the motor and it the wire from the top coil goes to cyl. # 3 and the bottom coil goes to cyl. #1. Is this correct or are they hooked up wrong? If they are wrong, then I guess that would throw my timing way off since I timed off the #1 cyl with the wire that is on it now.

 

[bradbettes]

Re: 1988 Mercury 60 hp loss of power / acceleration

Just did a compression test cylinder 2 & 3 both read 115. Cylinder 1 does not read anything. Also, when I thread the compression tester into the spark plug sockets for 2 & 3, it will only go in so far (about 1/4 inch of threads still out of socket). When I thread it into #1, it will thread all the way in until there are no more thread showing on the outside.

Not sure what that means, but it don't sound good to me.

 

[PHE]

Re: 1988 Mercury 60 hp loss of power / acceleration

Sounds like you have a dead cylinder. Running great, running out of gas, running great on a new tank of gas for a couple of minutes, then lossing compression in a cylinder, sounds like it didn't have oil mixed with the gas. You did put oil in the tank?

You can check the spark using the procedure I described earlier, by pulling the plugs, putting them in the plug wire boot, wrapping some wire around the threads of each plug, grounding it to the block and cranking the engine. But, I think you already found the problem.