85hp Chrysler bogs down after 30mins

[Shorebreak91]

Hey everyone! I've been lurking in the forums for a bit, but I have a nagging question about my boat. I bought a 1983 renken (I'm aware of their reputation) that came with an 85hp Chrysler. The previous owner said the engine was a bit finnicky and only liked to be started when it was tilted slightly out of the water. First trip out, it started up after a few goes and ran for about 20-30mins before it started to bog down while the throttle was wide open. It eventually wouldn't start again and I had to get towed back. This happened the second time as well. I checked the compression and it is all good on all cylinders. I replaced the fuel pump diaphragm as well, which wasn't really in bad shape. I also recently replaced the seals in the carbs and cleaned them all out (the floats seemed a bit misaligned with them hanging a bit too low when inverted). Once I put the carbs back on, it started up only after 2-3 tries and with some.ignition spray into the carbs (out of water using a hose on the engine). I'm still wary of it dying on me out on the water and I have read somewhere that maybe the coils are getting overheated? I've also thought about replacing the impeller, but I'm not sure. I appreciate any help!

 

[jerryjerry05]

The first things to do when you buy ANY used motor.
Compression and spark check.
Clean the carbs, check the reeds behind the carbs..
Then after it starts, change the impeller.
It sounds like the vanes have set and don't work well at high speeds and it's getting hot??

Also check the tank vent line. Bugs get inside and make nests and clog the line.

Cleaning the carbs, remove the air screws, before you do, turn them in till they hit bottom(gently)
remember how many turns it takes and reset to that setting.

The first 4 posts in the Force/Chrysler forum have a LOT of good info.
The link about "link and sinc" is a good one. You probably don't need it but read all the posts.

 

[Shorebreak91]

Thanks for the response! I've already measure the compression and it is in line with original specs. Sparkplugs are new and the engine starts up after a few tries just fine. The engine started up faster after I cleaned out the carbs and swapped in new seals. I'll check the link and sync thread as I kind of just adjusted the air screws by feel while the engine was running. The idle ( screws in the side of the carb?) were all screwed all the way down when I rebuilt the carbs in the first place.
the water coming out of the engine isn't too hot, so I'm not convinced the impeller is the issue, but I've read about the coils overheating, just not sure how to test to determine which is the faulty coil (they're expensive and I'd rather not buy all 3).

 

[jerryjerry05]

NOT idle screws.They're air/fuel mix screws for running at idle.
Start at 1 1/2 turn out on all 3.
The factory put out a bulletin that says, set the screws at 1 turn out and leave them there.
But some motors won't run at that setting, try and see what you get.

Never heard about the coils getting hot?
Usually they fail and that's it.
But they don't fail all that often.

It sounds like it's getting hot.
One of the best tools I have is a 16$ heat/temp gun.
Go for a ride and when the motor stalls? check the temps?

Rebuild the fuel pump?

 

[Trophy83]

The first 4 posts in the Force/Chrysler forum have a LOT of good info.
The link about "link and sinc" is a good one. You probably don't need it but read all the posts.

What do you mean by the first 4 posts? I have similar questions as OP.

 

[The Force power]

What do you mean by the first 4 posts? I have similar questions as OP.

The four yellow stickies at the top in this Force forum, here's another one
https://forums.iboats.com/forum/eng...ked-questions-faq/162217-outboard-won-t-start

 

[Shorebreak91]

NOT idle screws.They're air/fuel mix screws for running at idle.
Start at 1 1/2 turn out on all 3.
The factory put out a bulletin that says, set the screws at 1 turn out and leave them there.
But some motors won't run at that setting, try and see what you get.

Never heard about the coils getting hot?
Usually they fail and that's it.
But they don't fail all that often.

It sounds like it's getting hot.
One of the best tools I have is a 16$ heat/temp gun.
Go for a ride and when the motor stalls? check the temps?

Rebuild the fuel pump?

Ahh okay. So you are talking about the small screens in the side of the carb, right? Versus the screws at the bottom of each carb (with the spring). Small screws in the side are idle screws according to your response?

So far:
A) I'm getting spark at every plug (which I replaced)
B) Compression is good on all cylinders.
C) I cleaned the carbs, adjusted the floats and changed out the gaskets.
D) I changed out the fuel pump diaphragm before
E) I just replaced the impeller/housing as well

Overall, I have 2 main issues:
1) My engine never seems to want to start cold the first time without starting fluid. Then it'll start up right away even after being off (plugs are getting fuel etc.)
2) I think the engine still bogs down after 20-30 minutes of driving (I haven't tested this since I cleaned the carbs/changed the impeller, but it happened on both test runs before that).

 

[The Force power]

Ahh okay. So you are talking about the small screens in the side of the carb, right? Versus the screws at the bottom of each carb (with the spring). Small screws in the side are idle screws according to your reply

Overall, I have 2 main issues:
1) My engine never seems to want to start cold the first time without starting fluid. Then it'll start up right away even after being off (plugs are getting fuel etc.)
2) I think the engine still bogs down after 20-30 minutes of driving (I haven't tested this since I cleaned the carbs/changed the impeller, but it happened on both test runs before that).

Small screw on side of carburetor is the AIR/FUEL mixture screw in IDLE-MODE, not an Idle adjuster!
What are they set at currently?
the Idle gets adjusted/increased/ decreased by advancing/retarding the timing!

To set-up the motor a timing-light is necessary tool; without its just a guess job

I would start with replacing all fuel-lines incl. the one to the tank, make sure the choke-solenoid & levers are working/adjusted properly

 

[jimmbo]

How are you testing the Spark? Watching the plugs? Or are you using a Tester Homemade/Purchased and seeing if the Spark will jump a 7/16" gap?

 

[jerryjerry05]

The Chrysler 85 the latest years 83/4.
Screw/screen on the side? Far as I know there's only one screw on top of the carb.
Pics???

#2 test for overheat.

Poor starting unless you use starting fluid?? The choke working?
You might have a sticking float??

 

[Shorebreak91]

Thanks for all the replies! Really appreciate it!

1) Understood re the ideal screws (I'll take some pictures). They were screwed all the way in tight when I recently took apart/rebuilt the carbs. I haven't done anything with timing as of yet.
2) I checked the spark by just looking at the sparkplugs themselves, so I guess that isn't the best way to confirm (the plugs are definitely getting fuel as they are wet after starting, so I'm not sure why it doesn't start right away).
3) All fuel lines including that to the tank look clear and are fairly new
4) Again, there is a small screw in the side of the carb and then there is a longer screw with a spring when intake the carb cover off (the big plate). I'll add pics. The small screws in the side were screwed all the way in tight when I first took apart the carbs.
5) The electric choke is definitely working open/close, it just doesn't seem to want to start up until some starting fluid/gas is sprayed into the carb intake. After that, it'll start up right away each time. When I took apart the carbs, I noticed the floats were hanging a bit low when inverted, so I leveled them and checked that they were hanging properly when in the correct position.

I replaced the impeller, so I would hope overheating would no longer be an issue, but I also am not 100% sure that the coils are not overheating (again, not sure this is a thing).

i don't have a huge issue with the engine not starting right away, but I'm more worried that I'm going to bog out again after 20-30 mins.

 

[The Force power]

Did you clean the orifices on the carbs when you had apart???
Please post pictures, because your explanations about the "screw" makes no sense
There's ether an air-mixture screw on the side OR its in the front above the intake
SET THIS AT ONE & HALF OUT turn out from slightly seated see how it runs on idle/start

Again....changing the Impeller is great;did you put the key back???

Is it bogging down??? after you did adjust the floats??

 

[jerryjerry05]

Yea where's the pics??
I wanna see the screw on the side??

What's the compression?

Had twin 88/85's the port motor wouldn't start with out starting fluid, unless
the motor was tilted 1/2 way up?
No matter what I did it just didn't want to start when it was down.

 

[The Force power]

{"Quote"** I'm more worried that I'm going to bog out again after 20-30 mins.{End Quote**

Did you check the vent in the tank? (as jerryjerry mentioned) if its plugged the engine can't pull-up the fuel

{QUOTE** When I took apart the carbs, I noticed the floats were hanging a bit low when inverted, so I leveled them and checked that they were hanging properly when in the correct position.{END QUOTE**

What did you level out; the tap that touched the needle? OR the float side?

 

[jerryjerry05]

Still waiting for the carb pics??

 

[The Force power]

Still waiting for the carb pics??

A spare can of starter fluid in the boat is the solution

 

[Shorebreak91]

Sorry about the delay here! I've been out of town, so I haven't been able to send a picture. I saw another post about fuel leaking out of the carbs, which is something I am also seeing since I took apart/reassembled the carbs.

https://www.crowleymarine.com/mercury-outboard/parts/1214_40.cfm
The screws I was/am confused with are parts 23 versus 24. I now see that 23 is the idle screw and 24 is just a jet? The 24 screw was in tight when I took apart each carb so I assume it goes back in tight.

Took the boat out this past weekend and noticed a couple (new) issues.

1) Wouldn't start without start fluid, but then would start up right away (this is an old issue)
2) Noticed that my full throttle wasn't actually pushing the throttle all the way open, so I assume I have been losing out on some top speed etc here
3) In neutral it would hit high RPMs (as high as I could go with the safety mechanism in place preventing me from opening the throttle all the way up), but under load I could only hit around 10mph at full throttle. This seems like it is directly linked to my carbs being re-built incorrectly/the floats being positioned wrong? Before I took them apart, I was at least hitting 28-30mph with 3 people in the boat despite the other issues I had (engine bogging down after 20-30 mins).

 

[The Force power]

#25 is the fuel-jet
#23 is the air/fuel mixture screw when in IDLE-MODE
NOT AN IDLE-SCREW, Idle rpms are adjusted by adjusting spark-advance

 

[Shorebreak91]

Ah got it! So both 24 & 25 should be clean and in tight?

 

[The Force power]

yes