1976 Johnson 85hp V4 Starts on Muffs Not in Lake

[gm280]

I know this shouldn't be done, but have you tried to crank it out of the water at the lake and then back it in the water? You could initially back the engine into the water, crank it over for a few turns to get some water into the engine, and then pull the trailer forward out of the water to see if it cranks. If so, back it in as quickly as possible to see if it stays running. JMHO

 

[Woodonglass]

It runs in the lake but... not ver y well AND as soon as I give it throttle it dies. Been House hunting last couple of days so no progress. Hope to get to it this weekend. Thanks for everyone's comment.

 

[gm280]

It runs in the lake but... not ver y well AND as soon as I give it throttle it dies. Been House hunting last couple of days so no progress. Hope to get to it this weekend. Thanks for everyone's comment.

So moving from boat projects to house projects? You do know that most house projects don't get repaired with polyester, 1708 and CSM don't you?

 

[dave2517]

Fyi...just my .02 anytime I test my OB, a 1977 johnson 85....I do it in a barrel....I have cut the top off of a plastic 55 gal drum to fit....this is more telling IMO...plus it ensures the water pump is working properly and not the water pressure from the hose

 

[hsdtech]

Sounds like a dead cylinder. First thing I would do is check compression. If that checks out I would do tests with the motor in a barrel of water at home until the problem is figured out.

 

[Woodonglass]

Now I'm Really perplexed!!! Just got my NEW Compression Checker (found out my B.I.L took the old one with him when he move to Virginia) I went out and checked all four cylinders and...#1 = 100psi, 2,3 & 4 = 105psi Not Great but...from what I've learned here on the forum well within running range. Haven't checked the spark yet. But, as stated before, it starts and runs great on the muffs. I DO have to spray some fuel in the fogging hole for the first start up, but after that she fires on the first bump usually. If it was an ignition or spark issue why would this change when she's in the water? Again, I'm just working on Logic here, and have NO mechanical skils other than what I've learned here on the forum. If I do get a good arc on the spark...Where else do I look. I can't imaging it's a carb issue cuz it would run bad on the muffs...Right??? I'm really bummed cuz I WANT to get on the water before COLD!!! I'm to much of a C.O.B to take it to a shop and spend $250 bucks for it.
But, maybe that's what it's gunna take.:noidea:

 

[Willyclay]

Mike, I held off posting in your thread because I have zero experience with that particular motor. However, my old geezer brain tends to lean toward the simple stuff. F_R posted a comment about back pressure and I try to pay attention to his guidance. Obviously on muffs, there is relatively no back pressure. The deeper that old beauty sits in the water at the lake increases the back pressure much like the old teenager trick of stuffing a potato in someone's car tailpipe. The motor will not be happy! BTDT but it was with a plugged up catalytic convertor. Any chance the two exhaust relief holes on the rear housing are being submerged due to the weight of the V4 on your boat? Can you try to start & run your motor at home but in a trash can or barrel to simulate the lake? NOTE: The experts, which I am not, recommend you not run your motor over a high idle RPM like 1000 while in neutral or in any gear while on muffs or in a barrel. Wish I could be more helpful. Good luck!

 

[Willyclay]

Could not edit my previous post so had to make another one to provide a link to a graphic about engine mounting height. Your anti-ventilation plate should be close to level with the bottom of the hull. I do better with pictures than words!

http://continuouswave.com/whaler/reference/engineMountingHeight.html

 

[jimmbo]

Rereading your original post "In neutral, at idle, I was at the motor trying to rev her up with the linkage and as soon as I would attempt to rev...she would die." When you say linkage, do you mean you had the throttle cable unhooked and you were advancing the throttle? Or were you just opening the carbs? It sounded like you had the carbs off the engine. When you put them back on, did you do a link-and-sync? Also when you are starting the engine, are you using the fast idle/warm up lever?

 

[Woodonglass]

Thanks Guys!!! Motor height is as it should be. The motor started fine in the lake and ran like a scalded Dog when I had her out last season but...She over heated due to my mistake re-installing the lower unit and not getting the water tube connected. I corrected that and I am 100% certain it's installed properly now. I do not currently have a barrel but...That could be a possibility in the near future.

jimmbo, I tried both, using the control box AND using the carb linkage. Same results. I believe the carbs are set correctly due to my previous statement about how well she started and ran the previous outing. NOTHING has changed on the motor since then EXCEPT the removal of the lower unit and re-installation. Motor, Carbs, Cables etc...were not touched. So again, Since this is the case I just can't figure out why she's doing this especially now since the Compression test didn't reveal any anomaly. I may put her back on the muffs and see if she'll start and run as before and if so, I'll look for a barrel to but her in. IF she runs great on the muffs again and then I put her in a barrel and she "Acts Up" again...what do I do. since compression is OK, what's the next thing to check?

 

[Willyclay]

Do you Okies have dirt daubbers/mud wasps out there like we do over here at The Edge of America? I removed an incredible amount of mud from my Johnson 100HP V4 exhaust tube after I stored it outside one year. Just drawing on my experiences to try to find you some help.

 

[jakedaawg]

With compression that low you will have a hard time getting it to run well if at all. Cold starts will also be problematic.

 

[Woodonglass]

With compression that low you will have a hard time getting it to run well if at all. Cold starts will also be problematic.

Don't think I understand your statement??? It starts and runs great on the muffs. If the compression was so bad that it was causing the motor to run bad wouldn't that be the same on the muffs? I dunno, just asking.

WC
We sure do but I have checked that as well, and I would think that if there was some Exhaust blockage that would have effected it when running on the muffs as well. Dumb Okies don't have a clue!!!

 

[jakedaawg]

I was referring to under a load or in the water. Muffs dont count. I can probably get one to run on muffs with 80psi. Muffs tell you little, in my shop we only use them to warm something up. Any testing or trouble shooting is done in the tanks or with the dyno. I realize those are not options for most.

You could try redoing the carbs. But i doubt thats your issue. Running well on muffs doesnt tell you dont need carb work becausr there is no load. A small amount of fuel will spin an unloaded engine really well. Not so much when it has to overcome back pressure un order to breath. Remember, a motor is basically just an air pump.

 

[jimmbo]

Are you getting a strong spark at each cylinder? I can't recall if the ignition coils are mounted on the cylinder heads in 1976? If so, perhaps one or more were damaged during the overheat, or their grounding was compromised.
After that I would recommend pulling the exhaust cover off and looking in the exhaust ports checking for signs of scuffing and scoring. This is the area that gets hottest first.

 

[Woodonglass]

I appreciate the input. Here's what is bothering me. Last Sept, I put her in the lake, fired her up, IN the lake, and she ran GREAT until the alarm went of. I IMMEDIATELY shut her down and started waving at boats and sounding the horn till someone came and towed me in. I let her set all winter and then did the repair in March on the water tubes. Took her to the lake and she wouldn't start. No Pre Starting on Muffs at home and I ran the battery down. Why would it start this between now and then. Nothing has been touched except the lower unit. I'm gunna check the spark tomorrow. What's the best way??

 

[jimmbo]

Using a spark tester. Not too hard to make one. Basically a well insulated wire that can be inserted into the spark plug boot that goes to a 7/16" gap in which the other end is grounded.

There are parts on the engine that are heat sensitive that may have gotten hot when the engine overheated. Some groundings may have loosened then corroded. the engine may not be firing on all cylinders. On on the muffs it may run on two or three of the four cylinders, but once the restriction of the exhaust occurs being in the water it can't run, or for very long.

When you checked compression, did you have the carbs wide open? Your compression dropped from the low 130s last year to around 100lbs. Also after you took the first readings, did you squirt some oil into the cylinders and check the compression a second time?

Maybe the carbs are gummed up. You overheated it last fall and put it away for the winter. Did you winterize it as in running stabilizer thru the fuel system?

 

[bktheking]

On my 4v the power packs had ground leads that had intermittent ground contact that caused me issues.

Another piece of info - after I did my merc carbs (1000ss) it would run great on muffs, as soon as it went into the lake it was a bear to start and I couldn't get it to move off idle- the carbs needed to be synced in order to get it to do anything. 1- get someone to operate the throttle without it running and look for any anomalies that may present themselves. 2- if the carbs haven't been cleaned clean them- you said you shut if down after it ran hot and left it over the winter- bad gas will wreak havoc on carb internals- the slightest amount of dirt in the high speed side will make it behave the way it is.

If that isn't the issue perhaps it's an exhaust issue- partially plugged as suggested.

 

[Woodonglass]

Ok, thought I'd give a final update. As I stated in my first post...I ain't no mek-a-nek but I AM a C.O.B. but...I finally had to admit defeat so a broke down and took the motor to a guy with 35 yrs experience working on Johnson/evinrude Motors. LOL He had her running like a Top in 2 hours. Pickup sensors under the flywheel were all caked up and he polished em up and she was running better. Power pack had issues toom, so a like new used one was installed and Now She runs like a Scaleded Dog!!! I shoulda done this a LONG time ago!!! Thanks to all for your suggestions and help. Much Appreciated.