'84 seahorse 70hp slow acceleration/stall

[bp1313]

Hey all,

The problem I'm having is that I'll go out fishing and the motor runs fine WOT (once I get her there), but getting her there is the issue. She starts up and goes into gear fine. If she's been off for 20 mins or more and I try to push the throttle to far forward she sputters and bogs. Sometimes she dies and I've got to start it up again and work the throttle lever to get it to stay running. The shift it into gear and it bogs again. While it's bogging down I find just the right amount of throttle and I can hear it slowly pick up. After a couple burps... she picks up and goes nicely. Once I've got it going I can throttle down and idle for a minute and then jump right back up with no bog or hesitation. It only seems to happen after it's been sitting for 20 minutes or more.

Recent carb kit/rebuilt, seafoam treatment (use it in all my gas), new plugs, fuel lines, bulb etc. It's just weird that it only happens after she sits for awhile. Once I've got it working nice at WOT.. I can throttle down and back up without issue.

Any thoughts on where to start? I've been looking around a bit and I'm hearing a bunch about the link n sync and adjusting the linkages and so on. I'll wait before I start doing any of that

-thanks

 

[Bosunsmate]

Re: '84 seahorse 70hp slow acceleration/stall

If you can do a compression test.
Pull your sparkplugs to check they how they look before you next start it up.

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

You have the EXACT SAME problem I have. Very similar conditions. My carb was just rebuilt, plugs are not new (since Feb. this year) but I have a new stator, fuel line/bulb, 2 new coils, etc. It's a fuel mix issue I think. MAYBE spark issue (spark plugs) but I'm thinking fuel to air.

I'm tagging into this thread in hopes that one of us finds a solution. This has been driving my nuts since my motor was rebuilt in Feb. this year. REALLY tired of this.

Mine has gotten worse and it's not 20mins any more. If you idle for a long time (such as trolling baits), it's the same thing as the 20min stop that you mentioned. If I try to get on the gas, you have to work it just right and after it spits/sutters a bit, she shoots off like a horse out of a starting gate.

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

If you can do a compression test.
Pull your sparkplugs to check they how they look before you next start it up.

Not to hi-jack this thread but.......I suspect it's not the compression. Probably not the plugs either. I know it's not the issue on my motor and I have the exact same symptoms amd I have checked my compression and it's good. Plugs are good too. I've changed plugs and the problem remains.

You should check the compression and the plugs as suggested though. You can either buy a compressioin gauge from an autoparts store or you can proabably rent one from O'Reily's or Autozone/Pepboys. As for plugs, they should be dry (not dripping with oil), and should not look completely black. A little black is ok but not excessive carbon buildup.

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

Just to share some info in hopes that it helps you find your problem, I was told to check the ignition for weak iginition components. My motor has 2 power packs (not sure about yours). I have already replaced the stator on my motor (what helps generate power to the packs and then to the coils and on to the sparkplugs.

I know that when my motor is acting up, it spits and sputters a little when it dies. That's a sign of of either flooding out. It's flooding out if it's getting entirely too much fuel. If it's getting too much fuel, there is not enough spark. It has to be an ignition issue.....it's just a matter of finding "what" and then replacing it if needed.

Also, weak ignition components are good when cold but when motor warms up, they start to fail. I'm really starting to lean towards a bad coil or power pack as the source of my problem and possibly yours. HOpe this info helps. Let me know if you find your problem!

 

[bp1313]

Re: '84 seahorse 70hp slow acceleration/stall

Don't worry about hijacking anything. All this information helps the cause.

My plugs and compression are fine. I have to believe it's a fuel issue because it makes no difference if it's warm or cold. Once she sits for a few... I get the issue when starting and trying to take off. If I start it up and rev the crap out of her out of gear.. she smokes a bit and I can hear whatever it is clear out. Once it's sounding good (a good 15-20 sec)... I can take off without a problem.

I'm wondering if there was something I missed getting exactly right when I rebuilt the carbs.

I did notice recently that I've got oil leaking out of the prop housing and below the powerhead. It's most definitely unburned (or burned for that matter) fuel oil mix. I hear that it can be normal depending on usage...but I think it might be a bit excessive lately. It's got to be at least a tablespoon of oil after I took it out on Sunday.

I'll keep looking and thanks for the info!

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

Sounds like your carrier bearing seal is going bad if you're seeing oil leaking out of the prop. You need to get that fixed. Fishing line could have caused it or just age. Replacing the seal is not a big task. I had my mechanic walk me through it and now that I've done it, it's a piece of cake. Just order a lower unit seals kit and or just the seal that's needed and you can replace it. You will need to do a compression test on the lower unit too before putting lower unit lube back in. I took a bike innertube and cut the valve stem and went to a hardware store and bought some tubing and fittings to make tube that I can connect to the lower unit and pump air in with a bicycle pump. Use a bike pump gauge to check for air leaks and spray soapy liquid around fittings for air bubbles/leaks. I fixed my problem in a couple of hours and learned a lot.

When I did this, I felt completely over my head but folks here are always ready to help you out. You may find a thread that I created about replacing the seal. If not, I'll try and help out where i can.

Do you have a repair manual? If not, you really need one. It can provide you so much more information and you will find it confirmed here by other members. It's amazing how much I have learned in the last 6mo of doing work myself and asking questions.


Now.....
As for your starting problem, I just got through reading my troubleshooting manual for my motor (79 model 85hp Evinrude) and my gosh there are a host of possibilities. It's easy to get lost and start chasing too many things down and that doesn't solve your problem, only frustration and wastes money.

So, first check compression as stated earlier. I know now why that's important and why it was stated first. Think of a motor as a glorified air compressor. If it's got an leaks whatsoever, it can cause the motor to not run correctly.

Then check for leaks around the crankcase, heads, carb flange to powerhead, etc. Use soapy solution and check for leaks. If you find one, make note of it as it "could" be the problem. Either way, it needs to be addressed but I'd move on to other tests to find other problems. COuld be a combo...

Then check the electrical system when it's acting up and not running correctly. I too have to use the fast idle to rev up the motor to get the motor to solve the fuel metering issue (improper fuel to air mix). It's probably running getting too much gas and not enough air. Or too mcuh gas and not enough spark (or both). Use an inductive timing light and clamp the timing light wire on a plug wire (when it's running poor) and watch the light (DO NOT stare into the blinding light, aim it at a dark corner or surface). The light should flash with a rythmic pulse and not waiver or intermittent flash. If it does, you found one of the problems or possibly "the" problem. This is the easiest electrical test to do.

If the timing light didn't turn up anything, you're electrical system should be good and now you need to look at possibly the carb.

For the carb, what altitude are you running your boat? Near sea level or near/above 3,000ft above seal level? That makes a difference too. I run 1,118 which is almost halfway between sea level and 3,000. I have a .025 jet in mine and I'm considering going to a .03 per my manual. For some reason, my mechanic used a .025 which is seal level usage and not what my manual recommended. This may resolve my issue but I think I still have a weak electrical component somewhere which is also compounding the issue.

You should be able to pull the jets without removing the carb. If you've rebuilt your carb, you should be able to get to your jets and check the numbers on the side. ALso, you should check your float level per your manual and spec for your motor.


Have you tried clearing the carb? Spray carb cleaner into the jets and let sit for a while. Then blast some compressed air from an air compressor blow gun into the primpary fuel line into the carb (the line between the carb and the fuel pump...disconnect from fuel pump and blow air into carb...this will clear it out and blow out any trash that may have blocked anything). I did this with mine initially and it helped a lot. Now my issues are worse and I've eliminated trash as a possibility and now look at the jet being too large causing the motor to flood out with too much fuel. It's causing it to smoke at idle, coughing (not firing correctly on one cylinder) and all of this added together is probably my issue. I think I have 2 or maybe 3 things that are working together to make my motor issues.


I gathered all of this info by reading my manual.........no joke. Between 3 threads that I'm following/trying to help with, I've learned a lot and feel I'm on my way to solving my motor problems after about 4 months!! YAY!

Keep us posted. I hope you find yours as well.

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

Sorry for the long post. I just "brain dumped" the last 1.2hrs of reading troubleshooting manuals and a repair manual. I tried to keep it simply but your issue is starting to sound slightly different than mine and I think you should keep it simple for now.

Air leaks
Spark check and lastly....
Carb checks

Everyone is quick to point to the carb I'm learning there are so many other things that it could be other than the carb. Thus why it's taking me 4mo of realizing.....it's not just the carb. It's an electrical issue too.

OH........and the sooner you fix it and the less you run your motor the better. If it's acting like it's not firing on all cylinders or idling rough, it's causing predetonation which is damaging the motor over long periods of use or a lot of idling (such as trolling/fishing). If it's coughing and dieing (like mine does) when trying to rev up the motor to clear it out, that's from the timing being slightly off or pre-detonation which damages your pistons/cylinders. So........find your problem soon and get it fixed. I know i"m making it a big priority for me since I just had mine rebuilt with all new pistons, etc. ALl this time, I've been thinking CARB issue......now I know where to look and I can eliminate it by process and deductive reasoning.

Amazing what you get by reading instructions huh... LOL! (typical man syndrome)

 

[bp1313]

Re: '84 seahorse 70hp slow acceleration/stall

lol wow! Great info I'm running at sea level here. I'll need to get me a manual soon. I'm not ruling out the carbs completely...but they were dismantled, soaked three times, sprayed with carb cleaner in all the orifices, and jetted out with air from a compressor. They were clean when they got put back on.

I'm not leaking out of the prop seals, it's fuel mix coming from the exhaust leaking down into the prop housing. I'm not totally worried about this, but there are times where I wonder if it's too much.

Compression tested out fine. 103 - 103 - 105 tested cold. I'm leaning toward needing to sync the timing and the carbs. Could be the plugs...but those are brand new and were sparking when tested. I think it's just off a bit and needs to be dialed in. Runs perfect after getting her cleared out...so I'm not thinking it's anything really major. Just some small tweaking.

I'm taking it out Saturday after some minor adjustments and we'll see what we've got. I'll look for a manual. What brand is your manual?

 

[CaneCutter79]

Re: '84 seahorse 70hp slow acceleration/stall

I honestly wish I could remember. I have 6 different PDF files and I think I bought it from "Outboardexpert.com". From the looks of it, they lowered the cost from what I paid several years ago. I also have an original hardcopy for my motor that I found on ebay. I recommend getting both. The electronic version is good and you can search and entire document for a keyword such as "timing" or "coil" and it show you all of the results. Helps you find things much faster. It also has a more modern approach to electrical troubleshooting whereas my old original manual uses older obsolete electronic testing equipment vs. modern DVA, etc.

Try this for a manual. You need your year and make only. I don't think it's narrowed down to model number.
1973-1989 Johnson Evinrude Repair and Service Manual

Oh........just had a thought.
You're motor may be trying to run in a type of safe mode. This prevents the user from screwing up the motor. Could be electrical issue somewhere. Getting a manual would help track that down. It's an 84 so.....I don't think it has a safe mode as those didn't appear until much later on electronic fuel injection engines. I'm still thinking you have an air leak or a bad coil/power pack.