Which model and year

[Sea Rider]

Which model and year is this Tohatsu, Nissan oldie ?

Has fuel knob at front, 2 round anodes at lower tail, can you tell if it's a 4C or 5B HP. no info or decals available. The plastic pee hose is very thin in diameter.

Probably was left with ethanol mixed gasoline for extra long period of time, came inside a used sailbooat, carb looks not to mention gaskets, diaphragm, all are worn.

Happy Boating

 

[pvanv]

Re: Which model and year

The carb is the style for a 5 hp - 8 hp 2-stroke. An owner added the anodes. You likely have a 5 hp pile of corroded junk.

 

[Sea Rider]

Re: Which model and year

Paul, the corroded junk will soon be operational as all electrical, mechanical related parts are ok, just needs a good overall clean up, carb kit, impeller, tail oil, plug change. How can you remove the carb's main nozzle, it's stuck, is it possible to pull it out from carb body with some tool ? Have soaked the carb in acrylic thinner for one hour, all parts are free now, except nozzle. Seems this will be a good rebuilding excercise. Can you give a aprox manufactured year for that junk as newer 5 HP models don't come with fuel selector at front ?

Happy Boating

 

[pvanv]

Re: Which model and year

Luis, I assume this is a 1-cylinder M5B. That would make it maybe a 1990 or so manufacture date, but as you know, year is irrelevant. If the nozzle is corroded into the carb body, extracting it will be a challenge... maybe if you make a tool to push it out from the carb throat side... In our shop, we would likely replace the whole carb, as once the anodizing is corroded, the carb will be a maintenance nightmare for ever.

 

[Sea Rider]

Re: Which model and year

Paul, it's a one cylinder 5 HP but could be a 4 also, which part are you reffering to as "once the anodizing is corroded" the whole carb interior/exterior or the general engine condition, Buddy want's to have that engine running at a minimum expense, new carb will be the way to go if having carb performance issues, but can't tell untill engines fires after long time being down. Other issue, both transom clamp screws are literally solded to both stern brackets, have applied, thinner, brake fluid, W-40 with no success, what would be the right product, method to free those parts ? Will the coup de grace, heating with a small gas torch work ?

Happy Boating

 

[pvanv]

Re: Which model and year

Once the carb is corroded, even if cleaned and working OK, any future exposure to even minor moisture (even from the air) will cause fantastic corrosion to grow. So likely time for a new carb. For the transom clamps... heat the screws and pray. The female threads should expand more than the steel screw, allowing it to come free, Also tap tap tap with a mallet, and use liberal amounts of PB blaster or other good penetrant.

 

[Sea Rider]

Re: Which model and year

Thanks Paul

Will follow your advise on carb issues if keeps clogging while in use and pray for the transom clamps to come loose before attempting any future part's repair.

Happy Boating

 

[Sea Rider]

Finishig the homework...

Finishig the homework...

Help, I need somebody, not just anybody to place LU back on !!

Near finishing the junk pile getting out the dark side to seeing light and ocean soon. After struggling with stucked clamps, alleluia, finally came loose after applying repetitive drops of brake fluid and letting penetrate deeply. Did receive the engine with leg insdie a box, to be sincere have not pulled down a 5 HP LU, mostly routine maintenance issues, our young park of 3.5/5 HP 2 strokes engines mostly are used as kickers and have very low hours on them. Need 4 precise tech answers :

1-Is the curve position of the cam rod correct as seen on picture ? When you install a new water pump housing & rubber seal, how smooth & depth must the rubber seal enter the housing's collar, picture shows broken upper collar, could salt formation have cracked the collar ? Any ideas ?

2-Near the drive shaft housing exit, there's a drive shaft bushing plate with several holes, was wondering if lever cam rod must pass through the upper hole marked with an X or side to grommet hole ?

3-What's the best position before bolting LU, shift lever must be at forward, neutral, reverse postion ? LU's rod must be at forward, neutral, forward position ?

4-Once you have LU bolted, assume once you have both rods lookig at each other you must place through grommet's hole the joint shift and secure it tight, correct ? The upper rod has a washer at the end that is secured by the rod's end as not to fall. Must this small washer be position at upper or lower joint shift border ? See pictures for parts detailed information.

Thanks in advance.

Happy Boating

 

[pvanv]

Re: Finishig the homework...

Re: Finishig the homework...

Luis,

Assuming you have an M5B...

1- The cam rod sweeps forward (as in your photo), so that it can meet up with the hole where it exits the exhaust housing. The rubber grommet for the aluminum water inlet elbow should seat well into the plastic wp housing. However, if it's not perfect, it should still be OK at low speeds, as the pump housing will still be submerged in water, just not necessarily cold inlet water. The grommet has a lug cast into it that helps you seat it in the housing.

2- When fully assembled, the top of the cam rod will exit through a rubber grommet, to trigger the tilt lock -- so that the motor will not tilt in reverse (but can tilt in Forward). We normally start with the brass coupler installed loosely on the upper shift rod, and the bottom of the coupler resting on the locking washer. Then as you insert the LU into the exhaust housing, guide the cam rod into the other hole of the coupler. Takes a bit of dexterity and coordination. As i recall, the rod does not pass through the bushing plate, but rather along side it. That way, you will be able to reach the coupler through the side grommet hole in the leg.

3- The coupler bolt will be easiest to access through the grommet hole when the shift handle is down in Reverse. Have the LU in Reverse also, and you will probably be in correct adjustment the first try. After snugging the LU bolts up, verify shifter operation -- to make sure the LU is in proper gear relative to the shifter handle, and if you need to make a slight adjustment, again do it when shifted into Reverse, for easiest access to the 6mm bolt (with 10mm head) through the grommet hole.

4- The coupler rests above the washer on the shift rod.

 

[Sea Rider]

Re: Finishig the homework...

Re: Finishig the homework...

Thanks Paul,

Yes assume it's a M5B, no stickers on cowl or engine plate availabe on that junk pile...

When you turn the rod as seen on the pic to opposite direction, the clutch seems not to engage on lower leg, so seems works only one way, is this issue correct ? Have you found pump case's broken necks when servicing older same 5 models ? Seems connecting necks should be a bit wider or rubber seals a bit thinner so to match evenly on hole. Will make an outside collar on pump's neck with epoxy just in case, should work well and seal all rubber seals with plastic glue where they match against respective connecting necks.

OK about lever and leg rod assembling position. If got you correct, first will need to position unscrewed brass coupler on upper lever rod with washer touching lower coupler, right ? then bolt lower leg, once both rods are in position slide coupler into lower rod and screw them tight using grommet's hole, then checking if lever works ok and adjusting coupler a bit if needed. Hole seems a tight space to work if having long fingers. Hate tu put back pieces that has not been removed by my hand, specially on models that don't know 100%. Usually take pics while in the proces of removing parts, or mark them with red fingernail paint as in adjustable rods heights.

Happy Boating

 

[pvanv]

Re: Finishig the homework...

Re: Finishig the homework...

Right. The cam rod only works one way. You will engage the cam rod (without tightening the coupler) before bolting up the LU.

 

[Sea Rider]

Homework is finished...

Homework is finished...

Paul,

Followed all your tech directives, the overall coupler work was pretty straightforward, didn't remember that the upper cam rod is attached to the drive shaft housing and moves the reverse lock arm vertically. Placing LU back to housing was a real nightmare, including backache. The drive shaft didn't want to enter crankshaft al all, threw the towel, had to go for the long job, removing complete head from it's base, flipped it over, found the head crank case and crankshaft with case's broken metal bits inside them, that's why shaft didn't want to enter a bit. Seems the last guy that stripped LU appart wanted to reinstall it and found to be a very tricky skilled job.

Removed old grease, cleaned all parts, changed lower head gasket, the internal pee hole was completely obstructed, passed a thin nail that cleared the obstruction, was not going to pee in one thousand years, raised the head sliding neatly without sweat into the greased drive shaft, tightened all six bolts under pan. The junk pile is now completely assembled, hope fires right up. How much metal portion is the head crank case missing ? Is it completely round tube like as seen on spare part list ?

Happy Boating

 

[pvanv]

Re: Homework is finished...

Re: Homework is finished...

Luis,

Looks like that pipe (head crank case) was corroded and abused. Looks like about half is missing. Similar part on the M3.5. Yes, it's just a tube. Probably will run "OK" with that one corroded/broken off like that.

 

[Sea Rider]

Re: Homework is finished...

Re: Homework is finished...

Luis,

Looks like that pipe (head crank case) was corroded and abused. Looks like about half is missing. Similar part on the M3.5. Yes, it's just a tube. Probably will run "OK" with that one corroded/broken off like that.

Paul,

If replacing a new head crank case, do you think will be much better for easiness of placing back LU in a future disassembling event that doing it with broken ends as seen on pic. The base all around tube is seen severly nicked and beaten by drive shaft while in the "process" of placing LU back on. Seems on 3.5-5 hp models, that placing LU back on is very tricky, would you say that removing complete head from pan will be the way to go for ease of re installation no matter if the job takes longer ?

Other issue, when you order a new head crank case, does it comes complete with inside other small parts like oil seals, upper gasket, or you have to order them separately ? Is it a must to change spacer that's located in midle of both oil seals, or can use older one ?

Was looking for the seal rubber that engages extreme upper water tube to head, can't find code part, apparently is missing, can see the part on spare parts manual inside figure 7-1, page 17, including codes for both lower seal rubber, items 26-28. Do you see same on your spare parts manual ?

Happy Boating

 

[pvanv]

Re: Homework is finished...

Re: Homework is finished...

Luis,

Pulling the powerhead is no big deal on those, so it might well be the fastest way to reassemble, especially with the bad crankcase head. As always, the seals and bits are ordered separately, unless you get a powerhead seal kit. You can re-use the spacer, but it's so cheap, it really doesn't matter either way. I've never had to change that square H-shaped rubber at the top of the water tube, but if you want one, your dealer can call Tohatsu to get a part number. Not sure if they are still available. You could always cut a new one out of thick neoprene gasket stock.

You are finding, as I had originally mentioned, that time and corrosion have made this "simple" job a big headache.

 

[Sea Rider]

Re: Homework is finished...

Re: Homework is finished...

Paul,

Incredible the junk pile fired right up on the second hard pull, won the bet that the engine would take long to fire up, just one small ooops. Experience teaches not to use again a used drive shaft housing gasket, the engine pees very well and some water is leaking into the pan through the gasket housing when giving more fuel. As the original is not available, will make one with proper material, engine is anxious to meet sea again next week.

Incredible that the H rubber part does not have a part number, the part is ok, just a bit dry out and still operative. Was checking the 3.5 part's manual and that same part (Grommet water upper pipe) does have a code 309-65031-1, wonder if that same part matches exactly the 5 HP ?

It's not the estenous time it has taken to totally rebuilt piece by piece that junk pile, was the challenge & overhaull course excersise just to take the nail out and the personal satisfaction and full divertimento achieving the homework done right.

Happy Boating

 

[Sea Rider]

Re: Homework is finished...

Re: Homework is finished...

After making, placing a thicker gasket and cutting broken head crank case's border to be even, sealed the upper unit back on, took advantage that the head was disassembled turned it up side down and filled with pure vinegar both cylinder head water instakes, let them soak for one hour, placed a nozzle on one w.intake connected to a hose and to house water line, opened the faucett, and all salt remains popped out, no need to change head gasket as the old one seems in excellent condition. While engine continued to be up side down sprayed a generous amount of power tuner into cylinder, piston & rings let soak for 1 hour, wiped with old toothbrush and rinsed with fresh gasoline. Now has better punch when pulling rope than before.

One dangerous issue found on older engines is that throttle cable is heavily rubbing against the bracket border that holds the wire cover into the assy, due to constant rubbing the threads of the wire tends to break and unroll from wire, when going near 3/4 or wot and backing throttle backward to slow down, the unrolled wire jams agains internal wire cover that is not smooth and locks the cable inside. Although the trottle grip seems to be backed, in crude reality the cable is still stuck inside cover at engine speed to which it was locked. The carb spring does not have the sufficient force to back throttle carb arm to it's resting position to slow down.

2 days a go a not experinced boater with a Mercury same model engine experimented a cable jam condition as explained and smashed against a pier at speed. Years back had the same problem with a Mariner, fortunately for me, the problem was detected at a close inspection and the bracket modified. It's just a matter of filing with a round file the bracket middle portion that rubs agains cable, once done, grease it with teflon grease.

When assembling/disassembling the trottle cable and securing the extreme with the screw provided, tightening metal against metal will deteriorate cutting the cable fast, one way to minimize this issue is to place the plastic cover of a 3 mm electric wire inside the barrel that holds the cable with a screw, flash cut evenly upper & lower borders, pass the cable and tight screw as usual. A good idea would be to solder the extreme of the cable so that wire doesn't unwrap from main cable package. Keep wire cover constantly lubricated for smooth operation. If someone suspects is experimenting rubbing issues, check with magnifying glass. Check pic for fast and reliable modification.

Happy Boating

 

[Sea Rider]

E future problems

E future problems

Having the little devil in excellent condition with all modifications done, went for a short sea trial, fired right up, after one hour noted a gas smell returned to shore to avoid a fire hazard and to the workshop. After complete pump disassembly the base was found craked at side, was patched with epoxic cement, hope holds fine untill new base arrives. Was nearly skocked to see that all new gaskets and diaphragams at such small use curled back when removed from base, if E-8 is doing so, can't imagine what E-10 will do. Conclusion: the longer they work with E the more that will extend making impossible to sit back nicely on pump's base.

So not to throw more gas into E fire, assume that from right now, we'll need to spend more money to change rubber related gas parts due to E premature deterioration, right ? Pics speak for themselves. E you stink!!

Unhappy Boating

 

[Sea Rider]

Maiden Voyage

Maiden Voyage

After fixing the pump base and before rib/engine was launched to sea, removed under pan flushing port and screwed a Tohatsu flushing adapter, opened faucett for max pressure, with forced water pees nicely, turned engine on, idled for 5 minutes, adjusted idle speed to factory specs. Launched rib/engine to sea and went for 1 hour testing, the engine purrs like a kitten with excellent peeing, was worth the cracked water housing total reconstruction along impeller change.

Although engine pushes rib nicely, from 1/2 throttle to wot the revs seems not to be increased, probably rib/passenger configuration is heavy including V medium deep v keel, more hull drag for prop to fight with, prop slipping on hub or low on compression ? Probably expecting too much power after running a 18 horse on same rib...

Happy Boating

 

[pvanv]

Re: Maiden Voyage

Re: Maiden Voyage

That's probably all the 5 will give you.