Guests - If You want access to member only forums on HSO. You will gain access only when you Sign-in or Sign-Up on HotSpotOutdoors.

It's easy - LOOK UPPER right menu.

  • RECEIVE THE GIFTS MEMBERS SHARE WITH YOU HERE...THEN...CREATE SOMETHING TO ENCHANT OTHERS THAT YOU WANT TO SHARE

    You know what we all love...

    When you enchant people, you fill them with delight and yourself in return. Have Fun!!!

Sign in to follow this  
ewirz

'98 Merc 75 hp question

Recommended Posts

Hello all. I have the motor listed above. I just had it rebuilt - new rings etc. I just got done with the breakin period. The mechanic had retarded the timing on it I guess to keep from accelerating hard. During the breakin, it ran fine other than it ran rough and hesitated a little while accelerating, but once at WOT it was fine (mechanic said that would be normal). I re-timed it (5 deg at idle and 18 at WOT) and ran it last night. Still hesitating when acceleration. Whats the deal? Did I not time it right? Carb need adjusting?

Shop tach showed 800-900rpm idle, 5100rpm @ WOT with 13.24x17 prop on Alumacraft 175 tourny pro.

It's not the fuel line (brand new), also had the fuel pump rebuilt, no water in fuel...Thoughts?

Thanks for the help

ERW

Share this post


Link to post
Share on other sites

If you choke it during acceleration (when it hesitates) does it pickup or bog out?

How about long runs at idle? Does the motor load up? I'm wondering if the carb settings aren't quite right and the motor is loading up prior to take off or to lean and starving for gas at acceleration.

When was the last time you had your carbs gone through? Did you run gas stabilizer through the motor prior to startup?

marine_man

Share this post


Link to post
Share on other sites

I didn't try choking it but I will and report back.

I had it idling for a long run last night (trolling), and didn't seem to be loaded at all (too lean?)

I cleaned the carbs this spring top to bottom. They were pretty clean. I think the mechanic re-adjusted them while he had it and he's not known for doing a good job in that department. I always run stabilizer.

I'll try choking it and re-adjust the carbs and let you know. Thanks for the help MM.

ERW

Share this post


Link to post
Share on other sites

Well, ran the boat quite a bit this weekend.

This is what I observed. If the motor was realatively cold, it hesitated accelerating, choking and/or squeezing the bulb only made it worse. If the motor was warm (like I had been trolling or driving around) it did not hesitate.

Manual says 7/8-1 3/8 turn out on the idle screw. I started at 1 and tried at 1 1/4 (on all three cylinders of course), no difference.

Carb cleaning in order?

ERW

Share this post


Link to post
Share on other sites

Did you try 7/8?

When you say cold, can you elaborate? Like right after startup?

Having to warm a motor up prior to take off is not that un heard off, although not always the norm on a 2 stroke.

marine_man

Share this post


Link to post
Share on other sites

I didn't try 7/8 but next time out I can.

I guess I use cold a little loose. I always let it warm up for a good couple minutes at idle or just above before hammering it.

Before the rebuild, never had this issue. Cold or been running for a while, it always jumped right out of the water, just seems odd.

ERW

Share this post


Link to post
Share on other sites

Just another thought....

If its running too rich at 1 or 1 1/4 turns, would it still hesitate accelerating? Also would it idle a little rough and fast?

It just seems like if the gas was a little rich while accelerating wouldn't cause the hesitation but would cause a rough idle and loading up....

Thinking out loud I guess. Thanks again for the help. I'll giver' a shot at 7/8 and see what happends.

ERW

Share this post


Link to post
Share on other sites

I would think that it may load up, which you said it wasn't, but I'd like to exhaust that chance first...

Where did you get your timing spec from? Unfortunately I don't have it, but it might be worth double-checking it.

marine_man

Share this post


Link to post
Share on other sites

I got the timing specs from the Clymers repair manual. I also double checked the id plate on the cylinder head, both the same.

5 deg idle and 18 @ wot.

Share this post


Link to post
Share on other sites

Just an update and another questions....

I triple checked the timing and I had it right. Although I forgot to set it at cranking speed, which helped (I think). I also found that the mechanic(if you could call him that) really screwed up on the throttle link and syc. I also found a few gas line clamps missing between the carbs that may have been leaking. After fixing all that, it runs like a top.

So the question....

Right now I'm running a 13.25x 17 aluminum prop on a '99 tournament pro 175. RPMs at WOT are about 5100 and getting ~33mph by my self, 1/2 tank and fishing gear. Hole shot ok but would like a little more speed if possible. I have a 19 pitch and get 34-35 but RPMs are around 4950. Can I move motor up a hole (on 2nd from top) or should I be happy with what I got?

Thanks again for all the help.

ERW

Share this post


Link to post
Share on other sites
Guest
This topic is now closed to further replies.
Sign in to follow this  



  • Your Responses - Share & Have Fun :)

    • So our bear friend came back today and she brought somebody with her. It might be time to quit feeding the birds sunflower seeds until next fall.  
    • I picked up that double bag deal about a month ago at Home Depot here in Sioux Falls. Ironically it was the same weekend we had the big April snow storm.
    • I see Home Depot advertising for Memorial day but no Kingsford double bag on sale. Has anyone seen any on sale anywhere? I am down to my last bag and need to stock up, Memorial weekend is usually the time to do it.
    • Found a cardinal nest in one of my shrub bushes. Cute little gray fuzzy things. I tried to take a picture, but my camera phone sucks, and I didn’t want to bother them. I’m so glad I spent $20 on a cardinal nest box, only to have it sit empty.
    • 20180519_060302.mp4 20180519_060302.mp4
    • Wisconsin's turkeys have survived my visit this year.  One is surely deaf after I managed to miss at 18 paces as he walked past me...  Not sure how that happened...   I feel like I rushed the shot when he started to get nervous.  Passed one jake the first morning that I could have taken at 40yd.   Came very close on two other mature gobblers.   One picked me off as he came around a hay pile at 20yd and immediately turned and ran, very smart bird.   The other came in hot, but decided to do a circle around me.  Appeared at 30yd wide open to my side while I was aiming down the sights towards his last gobble, and I had no chance to turn and shoot...  
    • Mentored for the Mn DNR women's Turkey hunt on Fri night and Sat morning. Friday was quiet but the birds flew up within 40 yards af the blind so we were hopefull for what the morning would bring. Sat morning was quiet and I waited till shooting hours to make my first yelps which were immediately cut off by 4 different birds. My lady was excited to say the least. She had never seen a turkey in the wild growing up and living in iron range.  Two of the toms gobbled a little after fly down but I could tell the were going north. The other 2 that were to our east gobbled a bit but shut up but sounded like the were coming down the road towards us. After about 20 minutes they rolled a big triple gobble within 60 yards wondering where this hen was at. I gave them a few purrs and set the call down getting her ready and calming her down for the shot. We still had not seen them put I could hear that unmistakable sound,pfffft boooom. Now I'm getting excited because I know they are danger close but they are on the side we can not see. Like always they proved me a fool and instead of coming right up the little road the cut through a high spot in the swamp and pop out in the field at 30 yards. They immediately hit full strut and throw a huge gobble right in our face and directly at my decoy that is set up at 8 yards. Then instead of coming right in they circle the decoy and blind at 25 yards and go to the side of the blind that is closed and gobble and strut for 15 min finally working into 8 to 10 yards bit still won't come towards the decoy. So I shut the one blind window and get her moved for a shot. The birds are now at 18 yards but getting skittish and moving away. As soon as I get the window open I hear her string drop and whay sounded like a hollow feathery smack and she says she got it. I look up and the birds are still there and look just a little nervous so I hit the call and they gobble back so I know it was a miss. So close but it was so much fun. Those 2 birds hung out for a few hours after strutting and gobbling at everything. 
    • Great bird, way to keep at it.
    • Nice bird, good job!
    • I assuming you are putting on the 5/16 T & G? I pushed mine tight and face nailed. Two nails per stud