Looper or not

It should be a looper. 85 was the 1st year of the V-4 and V-8 loop charged engines. It was also the year of the most problems. Be ABSOLUTELY certain which carbs it has and what to set the timing at. In 85 for the V-4, the 120 ran 18 degrees of timing, and the 140 ran 22 degrees of timing. They used the same carbs for both engines, but different jetting and relied on timing and the exhaust tuner to make the HP changes. this resulted in ALOT of burned up engines as they ran to lean in stock form, and overheated CONSTANTLY from the advanced timing. In 86 OMC made ALOT of changes, and many engines have been upgraded to 86+ specs. The changes were a different exhaust tuner, different carbs, different jetting, lowering the timing back to 18 degrees, and different reed valves. If you don't know which carbs you have, then assume it has been upgraded and run 18 degrees of timing. I upgraded mine to 86 carbs, rejetted, and ran 18-19 degrees of timing and it ran great. In stock form it kept melting down the #2 piston, and is how I ended up with it as the last owner got tired of rebuilding it.
 
Great thanks guys. Ferm ,that's a bunch of good information.I have been confused only because the mechanic I used a year ago told me its not a Looper,maybe that's why he couldn't get it to run properly
 
THEFERMANATOR said:
It should be a looper. 85 was the 1st year of the V-4 and V-8 loop charged engines. It was also the year of the most problems. Be ABSOLUTELY certain which carbs it has and what to set the timing at. In 85 for the V-4, the 120 ran 18 degrees of timing, and the 140 ran 22 degrees of timing. They used the same carbs for both engines, but different jetting and relied on timing and the exhaust tuner to make the HP changes. this resulted in ALOT of burned up engines as they ran to lean in stock form, and overheated CONSTANTLY from the advanced timing. In 86 OMC made ALOT of changes, and many engines have been upgraded to 86+ specs. The changes were a different exhaust tuner, different carbs, different jetting, lowering the timing back to 18 degrees, and different reed valves. If you don't know which carbs you have, then assume it has been upgraded and run 18 degrees of timing. I upgraded mine to 86 carbs, rejetted, and ran 18-19 degrees of timing and it ran great. In stock form it kept melting down the #2 piston, and is how I ended up with it as the last owner got tired of rebuilding it.
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This is EXACTLY what I was going to say. :sun:
 
wellcraftv20step said:
Great thanks guys. Ferm ,that's a bunch of good information.I have been confused only because the mechanic I used a year ago told me its not a Looper,maybe that's why he couldn't get it to run properly
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If it has a removeable exhaust cover between the cylinder heads, it's a crossflow, if it is a solid block between the heads it's a looper. And the 85 140 looper is a TOUGH SOB to get running right. I gave up on mine after the 3rd time rebuilding it for melted pistons, and upgraded it to 86 specs. No more troubles after that except for needing to jet the carbs differently to make it run right at idle and off idle.
 
The guy I recently took it to seems to have it running pretty well now, he changed the timer base and that seems to have solved the intermittent lack of power problem I was having . I took it out yesterday and it ran very well. only thing was the mechanic for some reason removed the shift cable anchoring bolt where it mounts under the cowel and when I pulled into the boat ramp I had no reverse, that was a lot of fun !! I am however very interested in finding out about that conversion.
 
wellcraftv20step said:
The guy I recently took it to seems to have it running pretty well now, he changed the timer base and that seems to have solved the intermittent lack of power problem I was having . I took it out yesterday and it ran very well. only thing was the mechanic for some reason removed the shift cable anchoring bolt where it mounts under the cowel and when I pulled into the boat ramp I had no reverse, that was a lot of fun !! I am however very interested in finding out about that conversion.
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I had to swap the carbs over to a set of 86(you can also run 87's, but you have to be careful as there are 2 different sets for 87), and drop the timing back to 18 degrees. Since the 85 140 uses a unique reed cage, it fows slightly different, and you will probably have to rejet accordingly. The cheapest thing to do is to set the timing at 18 and run the small carbs. It drops it back to a 120 instead of 140, but the lower timing is alot easier on the engine. Most shops set the timing at 18 because ONLY the 85 140 ran the extra timing(I don't think the 300 for 85 ran more than 18), and many manuals don't list it.
 
well I just checked it and its definitely a solid block between the heads so a Looper it is ! and I see that on top of the flywheel its marked at 18 degrees in red.
 
Get a known good tach and make sure yours is correct first. From your previous posts it sounds like your timing got set to 18 instead of 22 which would derate you to 120HP and cause your RPM's to be lower. I would stick with the 18 degrees of timing as it is ALOT safer on your engine, and reprop it to turn up to 5500-5600 or so at WOT.
 
Ferm, I swapped out the tack and I;m still only turning 4800 rpm's. I currently have a 15x17 aluminum prop, I'm confused on weather to change the size /pitch and or both. any suggestions ? thanks,
 
It sounds like you need to drop down to a 15 pitch prop for it. Also it may be worth checking to make sure it has the 2.25:1 lower unit gears. Alot of the V4 large gear cases fail, and get swapped out for V6 gear cases(same size), but the V6 case has 1.86:1 gears and the V4 version of it has 2.25:1 gears. Put the engine in gear, mark the prop and flywheel, and see how many rotations of the flywheel it takes for 1 revolution of the prop.
 
I took the boat out again yesterday and had the same old problem, she would run great for the first couple of minutes then start to miss and bog rite down to where I cant get the rpm;s above 2000. Yhen while going along at 2000 rpm,s and the throttle in the wide open position she would just take off like a bat out of hell. It clearly seems like the longer I run it the worse the problem gets. Now it sounds like fuel but I took that tank out and flushed it my self 3x's just to be sure I was eliminating any bad fuel issues. And I took this boat out last week with no issues what so ever !! It ran really well, She has a new fuel pump ( VRO removed), New Timer base new Power packs; Carbs rebuilt, Wires. plugs. Seriously stumped here!!!
 
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