1985 Johnson 185hp thoughts

[bsedwebt]

I picked up a J185TLCOC -- 1985 Johnson 185HP 20" V6 that appears to be fresh water used only as there appears to be no corrosion. It appears to have been rebuilt by looking at ALL the fresh gaskets, chipped paint on ALL the bolts, ALL new electrics - coils, wires, plugs, rectifier, stator, trim pump, new harness, etc. Rebuilt carbs look super clean. Motor ran great, idled smooth, very little smoke, no odd noises, pulled hard and ran about 50mph on a heavy, waterlogged 20 foot bass boat with 3 full sized adults and a less than perfect 24 pitch stainless prop on the boat I took it off of but is cosmetically challenged. From what I can gather the motor is a crossflow and should weigh in at 380lbs. The VRO pump appears to be new as well but has been disconnected and was being pre-mixed 50:1 with Johnson 2-stroke oil. I think 1985 is the first year OMC was officially prop rated and this motor would have been the same as an earlier model 200HP based on the weight. Fuel consumption did not appear to be bad for the hour I test drove it ranging from idle to wide open. What should I expect with this motor? Is it a workhorse or a weakhorse? Fuel consumption? Things to look out for before installing it on my boat? Thanks -

[keefallan]

It is the old 200 crossflow. Its not a weakhorse. It will run great. Keep the carbs clean..........it will run great for you. Crossflows run great, and for a long time. It will suck some gas up top, but at idle, its really quite good on gas. If its got all new electrical stuff and clean carbs, it sounds great.

[bsedwebt]

Thanks for that. I am reading some stuff where the heads can be changed to the older style heads and get more compression. I hear this motor tops out at 90PSI and if an older set of 200/225/235 heads from the late 70's are installed it will bump the compression to about 110-115PSI and increase the HP. Is this true? If so what heads and gaskets should I be looking for? I figure I might just as well bump it up now since it is going to be cosmetically restored before going on the big old 25' cabin boat.

[delawarerick]

If I'm not mistaken the 185 and the 155 were work horses commercial models the compression was kept low for longitivity. A friend had a 155 could not kill it was on a big old fish boat used a lot of gas under load but kept running. This was on a 25 privateer it pushed it close to 30.

[keefallan]

If I'm not mistaken the 185 and the 155 were work horses commercial models the compression was kept low for longitivity. A friend had a 155 could not kill it was on a big old fish boat used a lot of gas under load but kept running. This was on a 25 privateer it pushed it close to 30.

Yep. That 155 was a big bore commercial motor. But I dont think the 185 was. i am pretty sure it was a small bore motor. When you look at it, a 200 crank rated would be around 185 prop rated.

The v6 crossflows(mid to late 80's) were kept under 100 lbs of compresssion except for the 150gt/xp. The 328324/325 heads only make around 95 lbs of compression in a crossflow, if you're lucky you may creep up to 100. Only the tight heads put you above 100.

If you want to raise compression, you need to be more mindful of good gas as well. You can run 87 with the bathtub heads. if you want tighter heads, you can get any set of heads from a 150gt/xp (any years) and these are the good heads from the 70's......323456/457, 323872/873. There are a few others, but they are like unicorns............ you can expect compression readings 110 and better. I saw 125 with a set of wisecos and the 872/873 heads.......thats a really good compression reading for a stock headed v6 crossflow.

It will really help the out of the hole...the more compression. But honestly, will it make more up top? I am not convinced. It will, dont get me wrong. But just how much? I dont think its all that. My speculation is that it may give you 5hp, but that's about it. You will probably need to up the main jets as well. You need to at least check. But, I am thinking you will need to bump them up a number.

Dont get me wrong, I am one of the first guys to take a 150, put on larger carbs and the tight heads and gain 10 to 15 hp. But, you already have the 1-5/16 carbs. You would have to upgrade to 1-3/8 carbs and then retest the jetting. Thats the only way that you are gonna get the best bang for the buck.......tighter heads and larger carbs.

[bsedwebt]

I found a 1990 GT150 Johnson with good heads and lower unit - will these work on the 185? Will it be worth the effort? My lower unit is chipped up and this one is not - I was thinking it would be an easy swap than to fix the old lower unit chips

[keefallan]

The heads will work. The lower unit should work, but I know there can be different length driveshafts(minor differences). I used to think they would all work if it was a 20" motor. But, I have come to learn on here that that is not always the case. SO, I would measure the length of the driveshaft from the flange of the lower and compare that measurement to the old unit.

As for worth the effort, only you can decide. Its not gonna make it 5 mph faster. Put it this way, when I turned my motor from a 150 to a gt150, I only gained 3mph. That was carbs and heads being swapped. Just food for thought.

[bsedwebt]

the head that is on it shows part number 328325 - I guess that is the low compression head - It may not be worth it for 5hp gain. I wonder what it would do to fuel mileage.

[FUJIMO]

i wouldn't mess with it, if its as clean & good run'n as you say it is...just keep turn'n the key and enjoy it...

[FMP]

Build it to spec of the tight head 225hp or whatever it was, carbs and all and see if it still only makes 185hp.
Was thinking this would have come in useful, nice project motor.
https://www.screamandfly.com/showthr...ot-995-or-BRO&

[keefallan]

Build it to spec of the tight head 225hp or whatever it was, carbs and all and see if it still only makes 185hp.
Was thinking this would have come in useful, nice project motor.
https://www.screamandfly.com/showthr...ot-995-or-BRO&

Yeah, I was drooling over that one when it came up for sale. I even pm'd the guy or posted on that about the motor. But funds at the time and the fact that he was in Maine. If it were south of NY, I'd have made the drive from MD.

[FMP]

Bargain. Would enjoy building that.

[Mark Poole ModVP]

The later model cross flow V6's, such as the 1985 model were smoother running, especially smoother idling engines than the older ones. Yes, this is due in part to the lower compression. If it has VRO I would remove it. They were not ethanol resistant until after 1986.