Rebuilding Mercruiser 165 - GM 250 I6

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ethan169

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Yes you want them torqued to spec (85). The 12-15 is just to seat them all before you torque. I would bet your fine, probably just the seal causing the drag.
I hope your right. It just seems like an awful lot of drag from a rubber seal. Ill call the machine shop tomorrow and just double check that it was line bored. I have to image it was.

Thanks again.
 

ethan169

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A quick update.

I removed the crank and checked all bearings, journals, caps. Cleaned everything and re installed and plastiguaged each journal. Every one was within spec and the crank was still very difficult to move.

I decided to load up the block in the truck and bring it to the machine shop. The machinist said he would inspect it and see if it was assembled correctly and see if he could determine the problem. He suspected that the mains would need to be line honed. He called me back a few days later and said that he agrees it was too much drag on the crank and he mentioned that I had it assembled correctly. He measured the bores of all of the caps and I guess the #1 cap was on the higher end of the tolerance and #4 was under tolerance. He switched them and it was much better.

He then decided that it would be best to mill of a few thousandths from each cap and then line hone the entire set. He remarked the caps re-installed everything. Its of course perfect now.So that was another $200 of machine work. It sucks but i guess its a drop in the bucket.

The machinist seems to do good work and he certainly isn't the cheapest guy around. However I feel like this is something that should have been checked before it left his shop. I also noticed that one of the connecting rods was installed backwards from all of the others. 5 of them were installed correctly per my mercruiser service manual (#6 I think). But #2 was backwards. I took it to him and he checked. He confirmed that it was backwards although he said it wouldn't have mattered since there was no offset (or something like that) on these rods. Each rod has its own journal to ride on. Either way he removed and re installed it right there for me. It took about 10 total including time for his oven to heat up. The rods were reused since they were in fine shape. He explained to me that when they remove the rods they mark the front of them with a punch. This way the can be sure of the orientation of which to install it. This rod in question was marked correctly however on the reverse side there is a mark almost in the same spot that looks like it was there from the casting during manufacturing. So i could see it was an easy mistake to make. Either way he apologized and took care of it immediately.

So right now I have the crank/pistons/rings/cam etc all installed. I checked the gap on every ring (new from sealed power) and compared to the spec in my manual and they were all perfect. I expected them to be but at least now I know for sure.

I have new lifters on order and have installed the oil pump. I have also been cleaning and painting parts that I plan on reusing. Like the exhaust riser/elbow, intake/exhaust/manifold etc. I also have a carb rebuilt kit coming for the mercruiser/rochester 2GC carb from www.carburator-parts.com. Seems to be an excellent place for all carburetors. Rebuild kits or individual parts etc.

Ill take some pictures tonight and post them up to document the progress. I'm at the point now where I can actually work on this thing every night a little bit. I hope to have it ready to go for the beginning of the summer season.
 

ethan169

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Oh and I also need to figure out what to do for an oil dipstick tube. I think I have one from one of the engines I tore apart for this build but I feel like its been broken off at the end. How important is it to have the exact dipstick tube? I realize that the length will effect the oil reading. However I know when I go to put oil in the motor the first time I'll know how much oil I put in and look at the reading on the dipstick right then. Then Ill use that as my reference. I have the part number from the parts catalog for this motor but I cant seem to find it anywhere. I saw one used one on ebay for like $120 which seems crazy to me.

Mercury Part # 87718A1
 

ethan169

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I believe the caps were line bored as they had a fresh crosshatch on them. But I'll have to look at the paper work. When I checked the clearances with the plastiguage I don't remember torquing to spec. I the manual called for 12-15 ft-lbs. Wouldnt you want them at full torque to check clearances?

I'll give the machine shop a call tomorrow and report back.

Thanks for the replys!

Sorry for the triple posts but for anyone paying attention this comment might raise a question. I was wrong about the caps. They were not originally line bored or honed when I disassembled everything. I was thinking of the rod caps being line honed.

And the manual does not call for 12-15 lb-ft for plasi-gauging the bearings. It calls for full torque which is what I did. I was thinking of the the lighter torque for the seating of the thrust surface procedure of the crank. Full torque on the rear main and light torque on the rest so you can alight the thrust surfaces properly before full torque.
 

alldodge

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Line boring does make a difference. So far as the dipstick length don't know, but your method for setting first time would work for me
 

harleyman1975

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I'm on board. Thanks for the update. Will be excited to see it done. Looks like a sweet old boat. Nothing else to do up here in the frozen north.
 

Mark72233

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Ethan169, cool build. I didn't line bore my crank caps I just took a chance on both engines and everything so far seems to be ok. One was a little tighter then the other but both have cranked up fine and run smoothly at least sitting on the driveway running on a makeshift stand. I have ran both engine for about an hour each. True test will be under load in a few months. As far as the dipstick goes I have 3 spares just send me a PM with your info and I will send you one. The measurements are the blade length is about 12.25 inches the tube is total length of 6.25 inches. The add 1 quart of oil line is about 7/8" from the end and the full line is just shy of 1 1/2" from the tip.
 

ethan169

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Thanks for the reply's everyone.

Mark that a great build you have going there on that formula. I'm not sure how I missed it! Thank you for the measurments of the dipstick and dipstick tube. They will help out! Ill send you a PM right after this.

I should probably start a thread that encompasses the entire boat build as this one is just about the engine rebuild.

Ill try to get some updated pictures up soon.

Ethan
 

Mark72233

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Ethan, I finally got by the post office, that item is in the mail heading your way. If you need anything else just let me know.
 

ethan169

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Ethan, I finally got by the post office, that item is in the mail heading your way. If you need anything else just let me know.


Thanks Mark! I just received the package at the end of last week. I've been meaning to get on here to thank you and post and update. I really appreciate you sending that!

Here are a few pictures of the progress from the last couple of weeks. Not much but I'm doing at least a little every night after work. Sometimes its very little though. Life is busy but that's a good thing right?


Checking the gap of all the rings (they were all perfect out of the box but I checked them anyway with the factory mercruiser specs.) A few of them with the rings installed.


Pistons/crank and cam installed. I also installed the timing cover and oil pan yesterday. Its quite simple but I did alot of research on how to do it properly to avoid any leaks. I plan to run the engine on a stand before it goes in the boat so if I do discover any leaks I could redo it quite easily. However Id rather do it right the first time. The manual I have actually talks about a 1 piece oil pan gasket but I dont see any place I can buy one of those. I used the felpro gaskets. Cork sides and rubber front and rear. Also use permatex ultra copper high temp RTV/gasket maker. The oil pan that I installed was the one that came out of the boat its a 16 bolt I think. The other 2 pans I have are 24 bolt? They are both older and not in as good of shape. I cleaned the original one up and resprayed it. If it causes a problem by leaking I can just replace it with one of the others I suppose. I don't expect to have to do that though.

I just realised you can see my collection of 250 blocks/cranks/cams/heads/manifolds and other parts in the background.


The other side. I'll have to fire up the furnace in the garage so I can paint the block and head with some nice high gloss black. Right now its just primered still.


Another


A pic of some parts. I painted the elbow/riser and water pump. The manifold needs to be sprayed still. I want to double check it for cracks though. It looks good but I want to take a closer look at it first. I still don't know why this motor kicked the bucket to begin with. It looks like it was freshly rebuilt (some assembly was wrong. Discovered when I dissasembled everything) but never really ran or didn't run much.

I also have two starters and 2 alternators that I need to figure out what works and what doesn't. The origional starter seemed to be ok since I used it to do the compression test while the original was still in the boat. The alternators I have no idea though. Im still not quite sure how to test them,,


Cleaned engine bay and fuel cell is removed. I still have 5 gallons left of crap fuel left in the tank. I pumped out over 10 gallons already. It must have been almost full when it was left who knows how long ago. I'll have to replace that panel that goes over the fuel cell and figure out what to do with the carpet that covered it. I may drill some core samples of the stringers and transom to see how things are but I don't forsee any major issues. Hoping anyways...


Here is a pic of the Glastron in the stuffed garage bay with its "younger" sibling and some snow removal equipment which hasn't gotten much use this year. I'm hoping this summer I'll have the glastron ready for water and will be able to bring the scarab and the glastron out at the same time to get more people on the river with us. I need to make friends with more people that have boats. I dont plan on always having two boats.

pretty soon Ill make a thread that will be for the entire boat restoration/project and link this thread to it since this is mainly just about the merc 165.

Everybody have a great rest of the weekend and enjoy the Superbowl if your into that srota thing!

Ethan
 

ethan169

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So any thoughts on reusing the head bolts? For all I know they could have been new the last time this was rebuilt and have basically 0 hours on them. They have obviously been torqued before though. They threads don't look damaged and they dont look stretched. I was going to chase the block with a tap and the botls with a die to make everything nice and clean. Thoughts?
 

Mark72233

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ethan169, I reused all of my head bolts on both of my 250s. Since I had 5 engines I just went through all of them and visually picked the best looking ones. I had no issues when I torqued them down. Just give them a good look and if they appear good use them.
 

ethan169

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Thanks guys. I cleaned up the bolts last night and I think Im going to reuse them.

Ive got a head gasket and some other manifold gaskets coming this friday so I plan to get the head on this weekend. Hopefully in the next week or two Ill get this on some sort of test rig and be able to do a few test runs.

I still have to tear into the carb though. I haven't even touched it yet...
 

ethan169

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So the last few days I've been cleaning up threads on tapped holes and bolts to get ready to install the head this weekend. The head gasket should be coming today.

I'm looking at the fuel pump and it looks to be in good shape but I literally have 0 experience with mechanical fuel pumps.

Any suggestions on what to check for? The spring and cam rocker or arm have good tension and are not siezed. When I actuate the arm manually (only a little bit) it does seem to create Vacume and push air out.

Here are a few pics of what I've got.
 

Fishermark

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I would reuse the fuel pump and see what happens. It is easy to change out if necessary after everything is done. It is also easy to rebuild. There is still a kit available for those old pumps.
 

alldodge

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IMO the pump appears to be working, and it will continue to work for the time you have the boat or until 1 hour after it is used. Figuring if this is the original it's 35 years old. The pump is expensive and the worst thing that can happen is it starts to leak and puts gas in your motor. If not caught soon after diluting the oil it can damage the motor.

I would get another pump
http://www.iboats.com/mall/partfind...gd_poid=112251&gd_row=19&session_id=231897215
 

ethan169

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Thanks for the advice on the fuel pump. I'm going to take a closer look at it tonight.

I have another question unrelated to the fuel pump. Sort of...

On the intake/exhaust manifold there is a small tube that goes through one of the exhaust ports. This tube was basically rotted off when I removed the engine. The tube connected to the carb if I remember. Looking at the parts catalog for this engine it appears to be called a "choke tube". I assume this had something to do with delivering warm air to the choke mechanism?

Here is a shot from the catalog. Its number 14 on this picture.




Any idea if I can operate without it? Or if I need to replace it how I could remove it? I guess I could try to drill it out. Is there a tube that it slides into in the manifold or if the tube is removed from the manifold there is an open hole at the top and bottom of the port?
 

Mark72233

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Ethan we had one of our engines that had the same issue and yes it provides heated air into the choke mechanism. As the engine heats the manifold which in turn heats the air going into the choke and expands or contracts a spring which opens the choke butterfly. Living in Florida and using the boat normally in the summer we didn't need it but the air pressure coming out of the exhaust intakes would escape out of that small hole (which will slowly get larger) and makes a noticeable sound that is irratating when your hearing tunes into it and that is all you will hear while the engine is running. I needed to replace both of my manifolds so no irratating noises now. One of the manifolds from the donor engine which was unfortunately cracked along a water passage had the same issue and the previous owner purchased a brake line with fittings that matched the thread size of the carb and they drilled and tapped it into the manifold and it was like it was professionally done and was working. Just an idea and cheap and easy enough to try before you have to spend $600-800 on a new manifold. Also I reused both of my fuel pumps, you can buy rebuild kit but it doesn't come with a new diaphragm so that was a waste of time and money. If you find a cheap fuel pump and that would be anything less than about $120 it will be for a car/truck engine not a boat. On a car or truck engine fuel pump when that diaphragm cracks and leaks fuel dumps onto the ground and you can smell and see the gas leaking if that happens on a boat raw fuel leaking into the bilge very bad. On your fuel pump which is made for a boat engine there is a brass fitting on the very bottom. You would run a small fuel line from there up to another fitting at the base of your carb which is on the valve cover side of your carb. You may have a fitting there or a brass plug. That way if the diaphragm start breaking, cracking and leaking but is still giving enough fuel for the engine to stay running then this raw fuel makes its way into this line and dumps back into your intake manifold just under the carb. Your engine may start running rough/rich at idle and may just die from being flooded but no fuel hopefully into the engine crack case and more importantly no fuel into the bilge.
 
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