100hp mariner

dave 416 · Nov 28, 2012

Hi everyone I just bought a used boat with a 100hp mariner 1989 inline 4 . the motor was seized and I was hoping to rebuild it . this past weekend I opened it up and found that the top of the pistons around the top ring had many broken pieces and one had a large crack running halfway around it just above the piston pin . im thinking the timing or firing order was off a little . the interesting thing is that the cylinder sleeves have slid away the top of the cylinder .so I was wondering is there anyway to push them back in. thx for your help

Maxz695 · Nov 28, 2012

Re: 100hp mariner

The cylinder sleeve if in good shape can be pressed back up and then drilled at the tapered base area at the bottom and insert a pin on both sides to keep it in place.

dave 416 · Nov 28, 2012

Re: 100hp mariner

thx for the fast reply the sleeves are in great shape the bits of piston that broke off were to big to go down the sides who would do this sort of work and what do you think it would cost how about locktite

Maxz695 · Nov 28, 2012

Re: 100hp mariner

Fastbullet is the expert on this and can do the job or recommend the best way to do it. I would think that stainless steel stock rod can be obtained at any hardware store. Loctite should be used to keep the pins in place. He might recommend removing the sleeve and adding some loctite on the external area then reinstall. I, sure you,ll here from hime sometime today on this subject. One thing you must check is to make sure the ports are in line when pressing it back in. The covers may have to be removed in order to look through the exaust port and transfer port to be sure they are not resticted or blocked before drilling and inserting the pins. If a press is not acessible I would think you might be able to put a rag on a piece of wood and inside the cylinder then gently tap at the wood to coax it back up Trying to get the ports lined up a bit at a time as you go if there that far off

dave 416 · Nov 28, 2012

Re: 100hp mariner

it is a older motor and I woudnt want to spend to much to fix it I think theres about a 1/4 gap at the top of the cyl if I could put locktite in there and hammer the sleeve back in would that work

Maxz695 · Nov 28, 2012

Re: 100hp mariner

I would in any case after setting the sleeve get dowel pins of non corrosive material and lock the sleeve in place as it has already slipped once. You stand a greater chance on never having another issue with it at that point if the cylinders are as good as you say. The pins can be as small as 1/16th of an inch as long as it keeps the sleeve in its proper alignment.

dave 416 · Nov 29, 2012

Re: 100hp mariner

Ok max so would 2pins per cyl be enough also I guess the holes would not have to be very deep just enough to get into the block 1/8 inch

Faztbullet · Nov 29, 2012

Re: 100hp mariner

The slipped sleeves is what damaged the piston as rings fell into the gap while running. You will need to heat the block in a oven and take a block of wood and tap sleeves back into position as these are a interference fit from factory. I will have to look at a block to see where to pin it if possible. Usually sleeves slip from a overheated or lugging the motor.

dave 416 · Nov 29, 2012

Re: 100hp mariner

I bought the boat with the motor in its current condition I wish I knew how it was running Ive only taken out 2 pistons so far the other 2 have the rings stuck in the gap at the bottom of the cylinder and will probably need a push through the spark plug hole the 2 that came out had no scoring on the sides of them and the cyls looked clean

dave 416 · Dec 1, 2012

Re: 100hp mariner

update I'm having problems removing the last piston the ring on the top of the piston has opened up in the gap at the bottom of the sleeve I'm thinking of cutting up a pop bottle and jamming it down the side of the cyl anyone have any ideas

Maxz695 · Dec 1, 2012

Re: 100hp mariner

Push the piston back up to the top spread some removable sealant like rtv silicone around the grove to help the ring slide by. Let is set for a day or two until dry and yank the piston full force out of the cylinder. Then remove the sealer check the cylinder condition at that point

dave 416 · Dec 2, 2012

Re: 100hp mariner

I talked to a shop this week they said they would pin my sleeves for $60 a cyl maybe i will let them pull the piston as well it couldnt cost that much. one of the pistons I pulled out was perfect no damage at all so I need to buy 3 saw them on ebay used for $75 so this rebuild could work out

dave 416 · Dec 9, 2012

Re: 100hp mariner

update the block came back from the shop friday and it looks ok .the service guy there thinks the sleeves were pushed back by a hydrolic event possibly the motor running and ingesting water this could be the case because the boat this motor came off was only rated for 70 or 75 hp so the extra weight would have left the boat very low in the water yet there was no rust inside the motor .I checked the connecting rods and one is bent and will need to be replaced

Maxz695 · Dec 9, 2012

Re: 100hp mariner

good to hear the block is OK goos luck on the rebuild

dave 416 · Dec 9, 2012

Re: 100hp mariner

thx max the guy on ebay that has pistons for sale thinks he can find the wrist pins for them if he cant can I use my old ones thx for your help

Maxz695 · Dec 9, 2012

Re: 100hp mariner

if there is no wear on the pins where the needles ride then you can use your wrist pins. There should be no more than a slight side to side movment after assembling the rod to the wrist pins. If there too worn the piston will not hold staright in the cylynders and cause skirt and sleeve damage. There are many pistons some new on ebay that have the wrist pins with them. I bought three off there with the pins. There are other HP engine pistons and pins that will work with the 100 HP I,m using 115 pistons in my 70 HP. Just some info to help you find what you need. There is a difference between 4 stroke and 2 stroke pistons so be aware of that. http://www.ebay.com/sch/100200-hp-/111125/i.html?_from=R40&_vxp=mtr&_nkw=Mercury+pistons Not sure what style pistons you have but here, s a set cheap see if the domes are the same $80.00 free shipping http://www.ebay.com/itm/Set-of-Rods..._Accessories_Gear&hash=item20cdf09187&vxp=mtr

dave 416 · Dec 9, 2012

Re: 100hp mariner

ok max just ordered the pistons now the hard part waiting thx for the help

Faztbullet · Dec 9, 2012

Re: 100hp mariner

These aint even close .....
Set of Rods Pistons Part 694015 818052A4 Force Chrysler Mercury | eBay

carholme · Dec 11, 2012

Re: 100hp mariner

Dave;

Many people will tell you that things are available from Ebay and that's fine but before you spend your money, you should verify the p/ns or you will get burnt and it is happening more and more. Remember that this is an internet site and the information is worth what you paid for it. Always get p/n verification for your specific s/n from the manuals before you spend your money.

Hopefully, you got the post above and were able to stop the order.

Gerry

Maxz695 · Dec 11, 2012

Re: 100hp mariner

as stated not sure what parts you have check the part numbers

100hp mariner

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