broken rings and water in exhaust chest 1983 115

[wayneo99]

my engine began to have idle problems late this summer, I did a compression ceack and found low numbers on one cylinder.

1983 reman 115 flat back from OBR 2 yrs old this past spring.

no vro. max timing retared 2 degrees as per OBR

Just broke it down by removing the heads, intake, inspection covers and exhaust plates and here is what i found.

head gagkets looked ok

rings in the 2 cylinders on one side of the engine are broken on the exhaust side, standing at back of boat looking towards the front, the RIGHT side of engine where all the carb linkage and shift linkage is

milky oil in the exhaust chest up top near the bad top cylinder and a little on the opposite side on the top, nothing towards the bottom.

plugs are clean, piston tops all look the same all have black carbon.


my questions are is this a result of clogged carbs? both of them clogged.. it runs well at high spped and has over sized high speed jets per the OBR factory. just idles like crap.

water intrusion from some where or both?

 

[emdsapmgr]

Broken ringsets on this engine are a common failure mode for the crossflow V4 family. It's a high temp/lack of lubrication overheat which will break the rings and cause damage to the piston crown and face of the head. Can be from an overheat, or from a lean condition from the carb. Since both bad holes are on the port side of the engine, it's possible that it was severely overheated (a bad thermostat) which affected that head only. Restricted carb jets are always a consideration when a failure like this happens, but unlikely since it occurred on only the port side (same half) of the two carbs. You stated both head gaskets looked ok-the seal rings were intact on all 4 cyls.. A severe overheat can lead to distortion in the block and it's components-even the exhaust manifolds (covers) at the rear of the engine. If the covers were never re-torqued after first running the new block a few times, they could have loosened up during an overheat and let water into the exhaust chest. Your water leak is unusual, in that usually water affects the lower cyls first, not the top ones. I'd pull the exhaust covers off and look for leaky gaskets, or even casting porosity (causing an internal spray) at the top of the inner exhaust cover (manifold). Usually a new block will be treated to two new thermostats at overhaul time, so the overheat is puzzling.

 

[wayneo99]

EMD
It has never overheated since it was a new rebuild, I have changed the t stats and impeller at the beginning of both seasons I always look when running to make sure I have good flow from the exhaust holes which it does, like a garden hose.
I know it can run lean and get hot without the alarm but I have pay close attention to it all the time.
My mechanic friend who is old school J/E certified was very surprised due to the larger high speed jets that OBR wanted him to install.
the head gaskets looked good and I replaced it first and had the same low compression.

at this point im right back when I was with my 1979 85hp that was running on 3 cylinders 2 yrs ago.

the water intrusion is a new twist, and what else can be done about the internal over heating? water diverters were in the right place and passages look good. new sensors in both heads from OBR and I have tested the alarm system and i has worked fine

 

[emdsapmgr]

Sounds as if you have been diligently cautious with your new powerhead. Have you measured the head temps with a laser temp gun? Just because you have not heard a horn does not mean it's not overheating. Have you torn the carbs apart that feed the two bad cyls? Esp remove the high speed jets and visually check for any debris in them? You need to pull them apart and do an autopsy on them-looking for differences between the carbs on the good cyls vs. those on the bad cys. Have you replaced the fuel hoses under the cowling? That engine's original fuel hoses are not capable of handling today's ethanol fuels. The hose will break down and black bits of fuel hose can migrate down into the jets, causing a restriction. What did you fine when you pulled the exhaust covers off the back? As a point of information, I've added a pic of an inner exhaust manifold that had a casting porosity hole in it-sprayed tons of water into the exhaust chest when running.

 

[wayneo99]

I have used a heat gun several times and temps were good.
exhaust plates look fine except for the milky residue on the top not the bottom. I think they were new from OBR.
I have to take carbs apart and compare.
my mechanic friend wants me to split the case and see if the piston are coked po along the exhaust side and check to see if the exhaust ports have any sharp edges on them

its 30 over on all 4 cylinders so if its badly scored im done.

I iwll keep you posted over the next few weeks onceI get the pistons out

thanks

 

[emdsapmgr]

If a jet gets restricted, that cyl will run lean. That will cause that cyl to run hot internally-even though the water pump and thermostats are working just fine. You will probably not get a hot horn in this case, either. You may be able to salvage the case and rotating assembly, as long as there are not long grooves in the cyl liners. You can remove any piston skirt aluminum that may have transferred to the cast iron cyl walls with some muratic acid. Bombardier does make .040 over pistons for their crossflows, if it comes to that. Find out what caused the problem, first-then work on the solution.

 

[wayneo99]

i took out the 2 bad pistons and luckly slight scorring in # 1.s hould clean up with a ball hone. exhaust ports are sharp which needs to be camfered. I compared the 2 jets in the bottom of each carb and they are wide open, no residue in the floats bowls either.
the jets size is .62 which is larger than OEM as per OBR. the other ones are 27.
not sure why is burned up unless the timing was off but i did it with a good gun and the TDC was set correctly as well. I dont run it WOT much and not for long when I do.

I have to located 2 red rhino .30 pistons, thats whats in there now.

 

[wayneo99]

the exhaust plates are not original they look good, I did the water test with the inner plate and it was fine. still not sure why the milky oil was up top at #1 and a little at #2. maybe it became loose. there was some water residue around a few of the bolts on the outside

 

[racerone]

Are we 100% sure you can get 0.040" O/S pistons from BRP.---------In my area there are lots of rebuildable blocks available.-Dealers just do not rebuild them anymore.

 

[wayneo99]

just a hone is all she is getting, new rings and pistons in those holes and back together. So far this engine has sucked up way to much cash and If it runs ok i will keep it if not it will be parted out.

hind sight is 20 20 ....

 

[emdsapmgr]

The engine should run with the .062's, maybe just a little overfueling. It should pull strong till you get to mid 5000's then may overfuel. Slightly. Should not be an issue. Carbs sound clean, normal. Make sure you use a gasket sealant on both exhaust covers. OMC sells it in a small can with a cap applicator. Or a similar Permatex product. You may want to put a straight edge along the faces of the inner part of the inner exhaust manifold-could be warped. After you get the engine back together, and run it a few times, retorque the heads and exhaust manifolds. As you timed the engine, did you follow the factory manual and set it when the engine was running at 5000 rpm's? That engine's timing will creep 2-4 degrees from idle to WOT...if set while idling. You can't set it at idle unless you use the Joe Reeves method. That engine does not have the VRO type pump. Any possibility that you ingested some water into the fuel tank? Was the fuel fresh-not mixed with old fuel left in the tank? FYI, .040 over factory crossflow pistons: V4 85-140 hp 5006704. .040 Over V6 crossflow: 50006710. These are in their Parts and Accessories Guide.

 

[wayneo99]

.062 was required by OBR to maintain the 1 yr warranty. ran like a champ pulls hard and great hole shot even with the 2 bad holes. Timing was done at WOT several times and i made sure It was retarted 2 degrees.
the pistons that OBR uses are RED RHINO. I cant seem to located them except from them and I cant buy directly from them.

I have a 17 montauk with plastic above deck tank and It gets fresh fuel weekly as its a gas hog. I run a external spin on 10 micron filter.

I did re torque the heads after break in but not the exhaust plates.

and all the fuel hoses have been upgraded, water passages are clean and open and diverters are in the right spot, hell its only 2 seasons old in brackish mostly fresh river water.


its still unclear as to why is burned up

 

[emdsapmgr]

That engine was never designed to run with a fuel water separator in the system. Suggest you may want to remove it when you get ready to run the new powerhead. Esp since you keep fresh fuel in the tank all the time. When the powerhead got water in it, did you unscrew the gas/water filter and dump it out into a clear glass? Did you get any water settling to the bottom of the glass? Does not seem like you would have water in the fuel-if you did, the engine might run-but would not be able to make much hp. You would know it for sure. Any chance you have a fuel/air leak in the gas/water separator plumbing? You've set the timing correctly-to the spec.

 

[boobie]

Emds, why do you say that motor was never designed to run with a fuel water separator in the system ?? Just curious.

 

[wayneo99]

when the power head got water in it? only time I saw evidence of water was when i broke down the powerhead to find the problems and remove the pistons.

 

[emdsapmgr]

That engine shipped from the factory with only the inlet filter screen on the fuel pump. I'm a fan of the fuel/water separators, esp with today's ethanol fuels. Until the actual cause of this failure is known, it's best to eliminate any other potential cause for a fuel restriction, water contamination or fuel/air leaks. When you upgraded the fuel hoses, did you use just regular bulk hose, and did you purchase the special heat-formed factory fuel hose from the pump to the fuel manifold? This is one hose that should be purchased from the factory: 326597 This hose is made with a special heat-formed bend and will flow proper fuel. Bulk hose in this application tends to kink when bent around tight corners, causing a fuel restriction.

 

[wayneo99]

I talked to OBR today and they said the most common problem is a lean condition from a clogged carb, I think i have ruled that out. the second cause they think is "phantom spark" or a power pack double firing. I have one new pack and one old which is blue in color, not sure how old that could be. I need to see if the older one is on the side of the bad pistons.

they also said that a oem .030 piston can be used with their red rhino pistons

 

[Faztbullet]

Red Rhino are just repackaged WSM pistons. OBR does not use OEM parts in their reman's and also I am a OBR distributer and If you need parts from them PM me...

 

[wayneo99]

I checked and the new 2 yr old power pack is on the side of the bad pistons. Its a replacement from sierra.